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3Com 56K Owner's Manual

1. S Registers Function Setting 921 Break length 10 ms 10 922 XON character 17 23 XOFF character 19 S24 Pulsed DSR duration 20 ms 150 S25 DTR recognition time 10 ms 5 S26 RTS CTS delay time 10 ms 1 S27 Bit mapped functions 0 S28 V 32 handshake time 100 ms 8 S29 V 21 handshake time 100 ms 20 33 Bit mapped functions 0 34 Bit mapped functions 0 38 Disconnect wait time sec 0 S41 Allowable remote log in attempts 0 42 Remote Access ASCII character 126 S43 Remote guard time 200 ms 200 51 Bit mapped functions 0 53 Bit mapped functions 0 54 Bit mapped functions 0 55 Bit mapped functions 0 56 Bit mapped functions 0 S69 Bit mapped functions 0 S70 Bit mapped functions 0 Bit mapped registers have up to eight functions A complete list of S Registers Register Default Function SO 0 Sets the number of rings on which to answer in Auto Answer mode S020 disables Auto Answer SO 1 enables Auto Answer and the Business M odem answers on the first ring S1 Counts and stores the number of rings from an incoming call S2 43 Stores the ASCII decimal code for the escape code character Default character is A value of 128 255 disables the escape code S3 13 Stores the ASCII decimal code for the Carriage Return character Valid range is 0 127 S4 10 Stores the ASCII decimal code for the Line Feed char
2. NVRAM Options Setting Description Handshake option BO ITU T answer sequence Transmitter C1 Enabled Command mode echo E1 Enabled Online local echo F1 Disabled Training tone volume L2 Medium Speaker control M1 ON during dial through connect Result codes Q0 Enabled Verbal or numeric V1 Verbal result codes result codes Result code subset X7 Extended Includes all codes except VOICE Protocol response amp A3 Full protocol codes codes Serial port rate select amp B1 Serial port rate fixed higher than connect rate Carrier Detect amp C1 Normal operations Guard tone amp GO U S Canada Transmit data amp H2 Software flow control hardware flow control Record data software amp I2 Enabled flow control Analog data amp K1 Enabled compression Normal lines amp LO Normal lines Error control amp M4 Normal error control Link rate select amp NO Variable Pulse dialing typE amp PO U S Canada Record data hardware amp R2 Enabled flow control Data Set Ready amp S0 Always on Remote Digital amp T5 Deny RDL Loopback RDL Break handling amp Y1 Clear buffer send immediately C 4 APPENDIX C FLOW CONTROL TEM PLATE NVRAM Options Setting Description Stored telephone amp Z0 9 0 Blank number Caller ID CID 0 Caller ID disabled Word length 8 Parity 0 None DTE rate Kbps 19 2 Detected by each modem from the AT prefix of the amp W command that writes your defaults to NVRA
3. For your modem to Command Disable carrier loss redial ATS69 1 0 Enable carrier loss redial ATS69 1 1 Wait n seconds between losing the connection and ATS44 n redialing This command also defines the interval in seconds between dialing attempts in the that the first attempt is not successful Example Sending ats44 20 sets a 20 second interval between losing the connection and redialing 4 4 CHAPTER 4 DIALING ANSWERING AND HANGING UP Answering Calls Force Answer Mode Auto Answer gt Your modem can be configured to answer calls By default your Business Modem will not automatically answers calls For your modem to Command Go through the answer sequence when it hasn t ATA received an incoming call Or Manually answer a call You can set your modem to Auto Answer using the ATSO command For your modem to Command Receive calls unattended Auto answer enabled ATSO 1 this instructs the Remember to set your communications software to T answer on the save incoming messages and or files NOT receive calls unattended Auto answer disabled ATSO 0 Example Sending arso o will not allow your modem to receive calls when you are not present See the S Register summary in Appendix A S Registers for more information about instructing the modem to answer after more than 1 ring When your modem senses a call coming in it sends the result code RING to your computer goes off hook and negotiat
4. For your modem to Command Enable Selective Reject ATS51 6 0 Default Disable Selective Reject ATS51 6 1 Attaining Speeds Above 28 8 Kbps V 34 connections at 21 6 24 and 26 4 Kbps are common To get connections of 28 8 31 2 and 33 6 Kbps line quality must be pristine end to end In addition 31 2 and 33 6 Kbps connection rates are possible only when the device to which you are connecting also runs software that supports speeds above 28 8 Kbps Attaining 56 K Connections When a client x2 modem connects to a server x2 modem the path through the telephone network betw een the modems is subject to the following conditions for an x2 connection to be made A digital connection at one end ISPs or other online services must have a digital connection to the public switched telephone network PSTN M ost major online services have a digital connection to the PSTN Only one digital to analog conversion There can be only one digital to analog conversion in the telephone network between the x2 server modem and the x2 client modem Controlling the V 8 Call Indicate Tone The V 8 protocol speeds call negotiation and specifies a call indicate tone Providing the call indicate tone is optional For compatibility we ship the Business M odem with the call indicate tone disabled For your modem to Command Enable the call indicate tone ATS54 6 0 V 34 If you enable the V 8 call indicate tone expect to hear a sound like a fa
5. 543 200 Sets the duration in fiftieths of a second of the guard time ifor the remote access sequence S51 Bit mapped register See Chapter 1 Using the AT Command Set for instructions about how to set bit mapped registers Bit Value Result 0 1 Disable MNP V 42 for V 22 1200 bps 1 2 Disable M NP V 42 for V 22bis 2400 bps 2 4 Disable M NP V 42 for V 32 V 32bis V 32terbo 9600 14400 19200 21600 bps S Registers 1 7 Register Default Function Bit Value Result S53 126 Bit mapped register See Chapter 1 Using the AT Command Set for instructions about how to set bit mapped registers 0 1 Enable dial security 1 2 Enable autopass fallback 2 4 Enale local access password protection Enabling local access password protection disables the amp Zn s command which stores up to 10 phone numbers because stored phone numbers occupy the same space in NVRAM as the dialback numbers for Dial Security accounts S54 64 ymbot rate bit mapped register used primarily by 3Com Technical Support for debugging purposes Bit Value Result 0 1 Disable 2400 symbol rate 1 2 Disable 2743 symbol rate 2 4 Disable 2800 symbol rate 3 8 Disable 3000 symbol rate 4 16 Disable 3200 symbol rate 5 32 Disable 3429 symbol rate 6 64 Disable V 8 Call Indicate CI 7 128 Disable V 8 Mode 555 Trellis code bit mapped register used primarily by 3Com eg SND OB UNEO Value 1 2 4 8 16 32 64 128 T
6. DSR DTE duplex echo EIA EIA 232 equalization The mode in which the fax modem is capable of sending and receiving data files A standard modem without fax capabilities is always in Data mode Another way of saying modem The device that generates or is the final destination of data See data communication equipment Any setting assumed at startup or reset by the computer s soft ware and attached devices and operational until changed by the user A test that checks the modem s EIA 232 interface and the cable that connects the terminal or computer and the modem The modem receives data in the form of digital signals from the computer or terminal and immediately returns the data to the screen for verification Discrete uniform signals In this manual the term refers to the binary digits 0 and 1 See data set ready See Data Terminal Equipment Indicates a communications channel capable of carrying signals in both directions See Half Duplex Full Duplex See local echo Electronic Industries Association which defines electronic standards in the U S A technical specification published by the Electronic Industries Association that establishes mechanical and electrical interface requirements between computers terminals modems and communication lines EIA 232 was formerly known as RS 232 A compensation circuit designed into modems to counteract certain distortions introduced by the telephone ch
7. m Check your RS 232 cable to make sure it is not a NULL modem cable The Business Modem won t dial a You may need to change the DTR setting at the Business Modem If so see the chapter about Controlling EIA 232 Signaling a Make sure that the phone line from your wall jack connects to JACK port of the Business M odem m Make sure the Business M odem is connected to a standard analog phone line and not to a digital system typically found in offices and hotels m f the Business Modem responds NO DIAL TONE when you attempt to dial first make sure that the phone line is connected to the JACK port on the back of the Business Modem If you hear dial tone when the Business Modem tries to dial but it quickly returns off hook and reports NO DIAL TONE try adding X5 to the dial string for example sending ATDTX5 5551212 The Business Modem will ignore dial tone detection Problems That Occur Before Connecting 15 3 Double characters are appearing on your monitor This is a signal that both the Business M odem s local echo and your software s local echo are on Type the command to turn off your online echo ATF1 or turn your communications software s local echo off refer to your software s documentation After you dial the Business Modem reports NO CARRIER and then hangs up m Try increasing S7 and decreasing S9 to allow more time for the connection m Try calling a different device If you are trying to connect to an older
8. C 0 4 second on 0 2 second off 0 4 second on 0 2 second off 0 8 second on 4 0 seconds off D 0 3 second on 0 2 second off 1 0 second on 0 2 second off 0 3 second on 4 0 seconds off These are graphical depictions of each ring pattern ACs B mmm NEN a C mm Em NENNEN EH EN ENSEM D m mmm m Bo For your modem to Command Enable recognition of Ring A ATS70 0 1 Disable recognition of Ring A ATS70 0 0 Enable recognition of Ring B ATS70 1 1 Disable recognition of Ring B ATS70 1 0 Enable recognition of Ring C ATS70 2 1 Disable recognition of Ring C ATS70 2 0 Enable recognition of Ring D ATS70 3 1 Disable recognition of Ring D ATS70 3 0 Example Sending ats70 0 1 3 1 to your modem enables the recognition of ring types A and D only 4 12 CHAPTER 4 DIALING ANSWERING AND HANGING UP Result Codes When a call comes in with a ring type A or D the Business Modem will send the result code RING A or RING D respectively The Business Modem will ignore other ring types If S70 is set to 0 the default the Business Modem detects ring types A and B sending the result code RING for either ring type This function is identical to that of other 3Com modems that do not support distinctive ring If only one ring type is enabled the Business M odem will recognize only the enabled ring type and ignore all others It will send the result code RING only when it detects the ring type that s
9. HST ITU T V 32 bis ITU T V 32 ITU T V 22 bis Bell 212A Supports ITU 56K standard server capabilities V 90 analog clients can call into your Business Modem to get 56K connections Up to 56 Kbps downstream and V 34 speeds upstream 33 6 31 2 28 8 26 4 24 21 6 19 2 16 8 14 4 12 kbps 9600 7200 4800 bps asynchronous Trellis Coded Modulation TCM 28 8 26 4 24 21 6 19 2 16 8 14 4 kbps asynchronous TCM 21 6 19 2 16 8 14 4 12 kbps 9600 7200 bps asynchronous TCM 4800 bps asynchronous Quadrature Amplitude Modulation QAM 16 8 14 4 12 kbps 9600 7200 bps asynchronous asymmetrical 450 bps back channel with automatic handshake adjustment to 300 bps TCM and QAM 4800 bps asynchronous asymmetrical 450 bps back channel with automatic handshake adjustment to 300 bps QAM 14 4 12 kbps 9600 7200 bps asynchronous TCM 4800 bps asynchronous QAM 9600 bps asynchronous TCM 4800 bps asynchronous QAM 2400 bps asynchronous QAM 1200 bps also V 22 asynchronous Differential Phase Shift Keying DPSK E 2 APPENDIX E TECHNICAL INFORMATION Error Control Data Compression Testing and Dialing Fax This modulation ITU T V 23 Bell 103 This ITU T V 42 MNP HST ITU T V 42 bis ITU T V 54 Supports 1200 bps asymmetrical with 75 bps back channel with Frequency Shift Keying FSK used by some U K and European phone systems 300 bps ITU T V 21 optional asynchronous Frequency Shift Keying FSK Su
10. J 5 FCC Notice Radio and Television Interference p This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interference to radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures wm Reorient or relocate the receiving antenna m Increase the separation between the equipment and receiver a Connect the equipment into an outlet on a circuit different from that to which the receiver is connected wm Consult the dealer or an experienced radio TV technician for help The user may find the following information prepared by the Federal Communications Commission helpful The CIB Interference Handbook and The CIB Telephone Interference Bulletin These documents are available on the Internet through the FCC Compliance and Interference Bureau Home Page at http ww w fcc gov cib lis
11. 0 1 Disable non linear coding 1 2 Disable TX level deviation Register Default Function 2 4 Disable preemphasis 3 8 Disable precoding 4 16 Disable shaping 5 32 Disable V 34 6 64 Disable V 34 7 128 Disable V FC 58 0 Bit mapped register See the beginning of this appendix for information about setting bit mapped registers Bit Value Result 0 1 Disable x2 5 32 Enables Disables V 90 S69 0 Bit mapped register See the beginning of this appendix for information about setting bit mapped registers Bit Value Result 0 1 Disable Plug and Play signaling 1 2 Disable M ulti link Tones S70 0 Bit mapped Register See the beginning of this appendix for information about setting bit mapped registers Bit Value Result 0 1 Enable recognition of Ring A 1 2 Enable recognition of Ring B 2 4 Enable recognition of Ring C 3 8 Enable recognition of Ring D eeee e e e e ALPHABETIC COMMAND SUMMARY This appendix contains an alphabetic listing of the AT commands to which the modem will respond Default settings are bold Basic Command Set Command Function Display help for the Basic command set Escape code Once your modem is online with another device the only command it recognizes is an escape code of three typed plus signs which forces the modem back to Command mode Do the following when issuing the command 1 Wait 1 second after sending the last item of data 2 Type 3 Wait 1
12. An error detection technique consisting of a cyclic algorithm performed on each block or frame of data by both sending and receiving modems The sending modem inserts the results of its computation in each data block in the form of a CRC code The receiving modem compares its results with the received CRC code and responds with either a positive or negative acknowledgment In the ARQ protocol implemented in 3Com high speed modems the receiving modem accepts no more data until a defective block is received correctly A type of communications in which computers and terminals are able to exchange data over an electronic medium When the transmitting modem detects redundant units of data it recodes them into shorter units of fewer bits The receiving modem then decompresses the redundant data units before passing them to the receiving computer A table of values assigned for each character during a call under data compression Default values in the table are continually altered and built during each call the longer the table the more efficient throughput gained If a destructive Break is sent during a call see the amp Y command causing the modems to reset the compression tables you can expect diminished throughput In this manual the term applies to modems that establish and control the data link via the telephone network data mode data set data terminal equipment DTE DCE default digital loopback digital signals
13. Display Querying and Help Screens Chapter 14 Testing a Connection Chapter 15 Troubleshooting Chapter 17 S Registers Appendix A Alphabetic Command Summary Appendix B Conventions Table 1 and Table 2 list conventions that are used throughout this guide Table 1 Notice Icons Icon Notice Type Description ig Information T Caution F Warning note Important features or instructions Information to alert you to potential damage to a program system or device Information to alert you to potential personal injury Table 2 Text Conventions Convention Description Commands The word command means you must enter the command exactly as shown in text and press the Return or Enter key You may also be asked to fill in values for variables Example wait n seconds between losing the connection and redialing ATS44 n This guide always gives the full form of a command in uppercase and lowercase letters However you can abbreviate commands by entering only the uppercase letters and the appropriate value Commands are not case sensitive Screen displays This typeface represents information as it appears on the screen The words enter and type When you see the word enter in this guide you must type something and then press the Return or Enter key Do not press the Return or Enter key when an instruction simply says type continued Key names Key names appear
14. control start bit Permanent memory not user programmable The Business Modem s factory settings are stored in ROM A feature that allows a remotely located user to view the Business M odem s configuration screens and change the Business M odem s configuration Password protection is available A test that checks the phone link and a remote modem s transmitter and receiver Data entered from the keyboard is transmitted from the initiating modem received by the remote modem s receiver looped through its transmitter and returned to the local screen for verification A copy of the data received by the remote system returned to the sending system and displayed on the screen Remote echoing is a function of the remote system Another way of saying status message The Business Modem sends result codes to your terminal for example to indicate the status of a connection The Universal Standard Order Code USOC standard for wiring a single line two wire phone network interface passing tip and ring signals typically from the public switched network See Read Only M emory A simple protocol that permits sending IP data over a serial line SLIP is being superseded by the Point to Point Protocol PPP A computer port that enables the transmission of data characters one bit at a time using a single electrical path Also known as a communications port or COM port On PC compatible machines this is a port for asynchronous seri
15. link Send atem4 unless you used a reset command ATZ or ATZ Testing the Business Modem using S Resister 16 14 9 Testing the Business Modem using S Resister 16 gt Analog Loopback AL 16 1D Register S16 is a bit mapped register See Appendix A S Registers for instructions for setting bit mapped registers For your modem to use Use one of these command Remote digital loopback with built in test pattern aATS16 4 or ATS16 2 1 Remote digital loopback using keyboard data ATS16 8 Of ATS16 3 1 Earlier modems require bit 3 to be enabled to grant digital loopback testing to a remote device The Business M odem requires the STA setting instead To perform remote digital loopback testing with a modem that does not use the amp T test command that modem should be set to S16 8 To use the modem s Test Pattern S16 bit 2 instead of typing your own data see RDL Testing Using a Built in Test Pattern S164 Send aT amp M0 amp N3S14 0 0 to the modem to prepare for testing This command disables error control fixes the connection rate at 2400 bps and makes the Business M odem return to command mode when you type 2 Send atsi6 1p The modem enters AL mode and sends a CONNECT result code The MR status light flashes 3 Type data to the modem for it to transmit loop to its receiver and output to the screen An alternative is to use the Test Pattern described later 4 Send the escape code and then
16. number Word length 7 Parity 1 Even DTE rate Kbps 9600 Detected by each modem from the AT prefix of the amp W command that writes your defaults to NVRAM Set your software to the desired word length parity and serial port rate defaults before sending the modem the AT amp W string C 6 X APPENDIX C FLOW CONTROL TEM PLATE eete RESULT CODE MEANINGS AND SETS Result Code Meanings Result Code Meaning 0 OK Command has been executed 1 CONNECT Connection with another device 2 RING Incoming ring detected 3 NO CARRIER Carrier Detect has failed or carrier has been dropped due to disconnect 4 ERROR Command is invalid 5 CONNECT 1200 Connection at reported rate Same meaning for results of 2400 10 4800 18 7200 20 9600 13 12000 21 14400 25 16800 43 19200 85 21600 91 24000 99 26400 103 28800 107 31200 151 33600 155 56000 162 or 64000 165 bps 6 NO DIAL TONE Dial tone not detected during the default 2 seconds set in Register S6 7 BUSY Busy signal detect modem hangs up 8 NO ANSWER After waiting 5 seconds for an answer modem hangs up returned instead of NO CARRIER when the option is used 11 RINGING The modem has dialed remote phone line is ringing 12 VOICE Voice answer at remote site modem hangs up 170 RING A Incoming distinctive ring detected 171 RING B Incoming distinctive
17. the only command it recognizes is an escape code or Revert to Command M ode without losing connections by sending ATS14 0 0 to the modem before establishing your connection Wait one second after sending the last item of data 6 Type Wait for ox to appear before typing any data You can change the characters used to revert to Command Mode or the wait time by resetting Register S2 or S12 For more information about resetting these S Registers see Appendix A S Registers There are two ways to return online using the ATOn command If you want to Command Return online ATOO Return online and retrain ATO1 Example Sending ato1 will allow you to resynchronize if you experienced errors during a non ARQ data transfer Controlling Local Echo 3 3 Controlling Local Echo Command Mode Local Echo gt Online M ode Local Echo gt There are two local echo settings one for Command Mode and one for Online Mode You can configure your modem to display the commands you type on screen by using the ATEn command If you want the commands you type to Command NOT appear on screen Command Mode echo OFF ATEO Appear on your screen Command Mode echo ON ATE1 Although you cannot see the command when you set ATEO the modem is receiving them To configure your modem to display a copy of data that is being transmitted on your screen you can use the ATFn command As the modem transmits data to a remo
18. you must be in Terminal M ode See Appendix A S Registers for a complete list of S Registers Understanding bit mapped S Registers A bit mapped S Register uses one number to describe a collection of settings Bit mapping allows us to pack a lot of information in a small space Bit mapped registers are in the form of Sr b n where r is the bit mapped register b is the bit n is O off or 1 on See Appendix A S Registers to see how bits are mapped into decimal values and for information about setting bit mapped S Registers oe ete e t e MODES OF OPERATION This chapter contains information about a Command and Online M odes a Controlling Local Echo a Data and Fax Modes Command and Online Modes If you want to Set the modem to Use this command Control the modem using AT commands Command Mode Escape Code Your modem set to revert to Command Mode when the Escape Code is used ATS14 0 0 Your modem to Disconnect when the Escape Code is used ATS14 0 1 Return to your connection after an Online Command Mode session Online Mode ATOO Send the modem commands while you are on line with another device Online Command Mode Escape Code DO NOT type ar before or ENTER after the command 3 2 CHAPTER 3 MODES OF OPERATION Entering Online Command Mode Returning to Online Mode When the modem is in Online Mode
19. 1 Fax Mode is the minimal standard for computer faxmodem interface Class 2 0 Fax M ode refers to the extended computer faxmodem interface If you are not sure whether your modem is in Data or Fax mode use the AT FCLASS Command If the modem returns a value of This indicates 0 Data Mode 1 Class 1 Fax M ode 2 0 Class 2 0 Fax Mode Whenever the modem is reset using the ATZ command or by turning the power off and then on it will reset to Data Mode 3 6 CHAPTER 3 MODES OF OPERATION e e t e DIALING ANSWERING HANGING UP AND This chapter explains how to use basic AT commands for wm Dialing wm Carrier loss redial m Answering calls a Making International calls wm Call detection a Caller ID functions m Distinctive Ring support Dialing Dial options You can use your modem to dial the specified phone number and execute dial options by using the following commands For your modem to Command Dial the specified phone number and execute dial options DO NOT use spaces or dashes ATD phone number Tone dial ATDT Pulse dial ATDP Pause for the length of time specified by S Register 8 The default is 2 seconds ATD Comma Pause for 125 milliseconds ATD Slash Wait for a second dial tone before continuing dialing This command only works only if the X3 or higher command has been issued see Chapter 7 Controlling Result Co
20. 2E 52 4E 42 4F 54 49 43 53 22 DATE 1015 TIME 2038 NMBR 8475550001 NAME U S ROBOTICS OK Using the CID command described below you can have the Business Modem send the information to your computer between the first and second RING messages The caller ID information is displayed only once RING DATE 1015 TIME 2038 NMBR 8475550001 NAME U S ROBOTICS RING The information remains in memory until either you reset the modem or until it receives another valid caller ID signal To be sure that the Business M odem receives the caller ID signal when auto answer is enabled set SO 2 or higher or make sure your communications software is set to answer on 2 or more rings Presentation Formats Commands The Business Modem sends the caller ID information to your computer formatted or unformatted Formatted presentation is a translation of the caller ID signal into ASCII text Unformatted presentation is a hexadecimal representation of the caller ID signal An Example of Formatted caller ID presentation RING DATE 1015 TIME 2038 NMBR 8475550001 NAME U S ROBOTICS RING An Example of Unformatted caller ID presentation RING 801E01083130313532303338020A37303835353530303031070C552E532E 524F424F5449435322 RING The following table describes the ATHCID n settings Caller ID Action Command Disable Caller ID detection and reporting AT CID 0 Default E
21. 3Com Technical Support representatives use to help you solve problems ATI11 Display caller ID information from the current call if in progress or the last call if between calls The caller ID information remains until either the modem is reset or until the modem receives another valid caller ID signal ATI15 Displaying Help The Business Modem provides six help or command summary screens basic AT command set ampersand amp command set percent command set percent command set dial command options D S Registers S and the octothorpe command set For your modem to display Command A partial summary of the basic command set ATS A partial summary of the ampersand command set AT amp A partial summary of S Register functions ATS A partial summary of percent command set ATS A summary of the octothorpe command set AT S p To see the remainder of the screen for any given command press any key eee e t e TESTING THE CONNECTION This chapter contains information about m Testing the Business Modem using AT amp Tn m Testing the Business Modem using S Register 16 Overview Your modem can perform digital and remote digital loopback tests You can use these tests to check the operations of the transmitter and receiver or to locate a problem with a remote device or a telephone line Testing is done by sending the AT amp Tn command or by setting Regist
22. 4 Bit 5 Result 0 0 Complete handshaking sequence V 42 Detection LAPM error control MNP 16 0 Disable M NP 0 32 Disable V 42 Detection and LAPM 16 32 Disable Detection phase if you know that the remote Business Modem does LAPM but not the Detection phase S28 Sets the duration in tenths of a second of the extra 3000 600 Hz answer tones sent during V 32 hand shaking This gives V 32 modems additional time to connect in V 32 mode before timing out If there is difficulty answering older manually operated V 32 modems for example modems that require a button to be pushed in order to dial try lengthening the duration of the extra tones Setting S28 to zero eliminates the extra tones resulting in a faster connect time if for example the Business M odem is set to use V 21 modulation 300 bps or V 23 modulation 1200 bps S29 20 Sets the duration in tenths of a second of the V 21 answer tone 534 Bit mapped register See the beginning of this appendix for information about setting bit mapped registers Bit Value Result 0 1 Disable V 32bis Used for troubleshooting 3Com Technical Support may ask you to disable V 32bis for testing purposes 1 2 Disable the Business M odem s enhanced proprietary V 32bis modulation Used for troubleshooting 2 4 Disable the faster retrains that occur during proprietary V 32terbo modulation Used for troubleshooting 3 8 Enable V 23 Required for some Br
23. 5 MNP5 compression If a Business M odem successfully establishes a V 42 error control connection with a remote device it also negotiates for V 42 bis data compression If a Business M odem successfully establishes an M NP connection with a remote device it also negotiates for MNP5 data compression The type of compression for a call if any is reported in the ATI6 display and in the CONNECT message if the modem is set to amp A3 Business M odems using V 42bis compression negotiate the following options and report them in the ATI6 display m Dictionary size that is the amount of memory available for compression table entries Entries are codes devised for redundant data The data is packed into shorter data units called code words and unpacked by the receiving device Possible dictionary sizes Bits Entries 9 512 10 1024 11 2048 Your modem uses an 11 bit or 2048 entry dictionary but they can reduce its size to accommodate a remote modem that uses a 9 or 10 bit dictionary a Maximum string length of each entry As the dictionary fills your modem deletes the oldest unused strings V 42bis compression is more efficient than MNP5 compression in part because it dynamically deletes entries that are no longer used In addition it works better with files that are already compressed These include ZIP files and 8 bit binary files M NP5 compression should NOT be used with binary files because it adds data to the fi
24. 9 gt gt gt 8 Carrier Detected 12 Speed Indicated 15 Synchronous Transmitter Timing p7 Synchronous Receiver Timing 20 Data Terminal Ready 4 22 Ring Indicate 24 Synchronous Transmitter Timing 4 DB 9 connectors for PCs should cable as shown below be wired at the computer end of the 8to 1 Carrier Detected 3 to 2 Received Data vv Male 2103 Transmit Data to 5 Signal Ground 22 ta 9 Ring Indicate 20 to 4 Data Terminal Read 5 to 8 Clear to Send 4 to 7 Request to Send 6 to 6 Data Set Ready gt Some computer terminal equipment supports only a few of your modem s EIA 232 signals The minimum required for your modem to operate asynchronously follows DB 25 DB 9 Pin Pin 3 3 2 5 20 4 Supports this signal Function Transmitted Data Received Data Signal Ground Data Terminal Ready Flow Control Requirements For Macintosh Computers Technical Specifications E 5 If your computer and software support Clear to Send and you wish to use Transmit Data hardware flow control amp H1 Pin 5 DB 25 or Pin 8 DB 9 is required If your computer and software support Request to Send and you wish to use Received Data hardware flow control amp R2 Pin 4 DB 25 or Pin 7 DB 9 is required If you re connecting your modem to a Macintosh computer we strongly recommend that you purchase a hard
25. Control Buffers Variable sizes Command Buffer 56 characters excluding the AT prefix Carriage Return and spaces Test Options Remote digital loopback digital loopback test pattern and dial test Failed Call Timeout 60 second default programmable 2 255 sec Answer Tone Timeout 60 seconds Answer Tone Detector 2080 2120 Hz Loss of Carrier Disconnect Timer 0 7 second default programmable 0 2 25 5 sec Equalization Adaptive Receive Sensitivity 43 dBm 2 dBm Transmit Level 9 dBm maximum Transmitter Frequency Tolerance 01 Certification FCC Part 68 Part 15 Class B Domestic IC Canada CS 03 UL listed Ringer equivalence 0 4b M ost computers provide a DB 25 or DB 9 port that conforms to the EIA 232 standard If you are connecting your Business Modem to a M acintosh computer see the section For Macintosh Computers E 4 The EIA 232 Interface Wiring a DB 25 to DB 9 Cable Minimum Requirements APPENDIX E TECHNICAL INFORMATION Your modem s serial port is factory set to signal according to the EIA 232 standard See Figure A 1 Signal s at your Business M odem s Serial Port Signal Ground Data Set Ready Clear to Send Request to Send Received Data Transmit Data jo Bo ow Chassis Ground DB 25 Connector Female Ay 1 O V OOOO 1 f 9 22 ii M7 15
26. Disable M NP V 42 for V 22 1200 bps 1 2 Disable M NP V 42 for V 22bis 2400 bps 2 4 Disable M NP V 42 for V 32 V 32bis V 32terbo 9600 14400 19200 21600 bps 6 64 Disable Selective Reject 53 126 Bit mapped register See the beginning of this appendix for information about setting bit mapped registers Bit Value Result A complete list of S Registers A 11 Register Default Function 0 1 Dial security enabled 1 2 Prompting enabled 2 4 Local access password protection enabled Enabling local access password protection disables the amp Zn s command which stores up to 10 phone numbers because stored phone numbers occupy the same space in NVRAM as the dialback numbers for Dial Security accounts S54 64 Symbol rate bit mapped register used primarily by 3Com Technical Support for debugging purposes Bit Value Result 0 1 Disable 2400 symbol rate 1 2 Disable 2743 symbol rate 2 4 Disable 2800 symbol rate 3 8 Disable 3000 symbol rate 4 16 Disable 3200 symbol rate 5 32 Disable 3429 symbol rate 6 64 Disable Call Indicate Cl 7 128 Disable V 8 55 0 Trellis code bit mapped register used primarily by 3Com Technical Support for debugging purposes Bit Value Result 0 1 Disable 8S 2D mapping 1 2 Disable 16S 4D mapping 2 4 Disable 32S 2D mapping 3 8 Disable 64S 4D mapping 7 128 Enable phase roll detection 56 0 Bit mapped register primarily used by 3Com Technical Support for debugging purposes Bit Value Result
27. Inc DEC and PATHWORKS are registered trademarks of Digital Equipment Corporation Intel and Pentium are registered trademarks of Intel Corporation AIX AT IBM NetView and OS 2 are registered trademarks and Warp is a trademark of International Business M achines Corporation M icrosoft M S DOS Windows and Windows NT are registered trademarks of M icrosoft Corporation Novell and NetWare are registered trademarks of Novell Inc PictureTel is a registered trademark of PictureTel Corporation UNIX is a registered trademark of X Open Company Ltd in the United States and other countries All other company and product names may be trademarks of the respective companies with which they are associated CONTENTS ABOUT THIS GUIDE Introduction Finding Specific Information in This Guide Conventions Related Documentation Year 2000 Compliance CONNECTING TO YOUR ISP Windows 95 98 What You Need Configuring Your modem with Plug and Play Files Needed By Your modem Installing the Latest Software Accessing Your Internet Service Provider Windows NT 4 0 and Later What you need Configuring Your modem Setting up RAS Determining if TCP IP is installed Installing TCP IP Configuring a PPP connection Configuring a SLIP connection Troubleshooting RAS M acintosh Handshaking Cable System Configuration Accessing the Internet M acintosh 230K High Speed script installation Installing the script Configuring Open Transport PPP Selecting the
28. Place the call again The phone company routes even local calls differently each time you call Call a different device to see if the problem persists The problem may be with the device you first tried to call If the modem is set to a fixed serial port rate amp B1 and your software is fixed at 19 2K 38 4K 57 6K or 115 2K bps the reason may be one of the following Many CRC errors a Your computer may not support the higher serial port rate If this is the case fix your software rate at 9600 bps If you use memory resident programs TSRs Terminate and Stay Resident programs or disk caching programs they may be interfering Try disabling them before you run your communications software Check that your software and the Business M odem are set for the same kind of flow control either hardware or software Some communications programs also require that you disable the type you are not using Send AT amp F1 to enable hardware flow control and other optimized settings Try a different file transfer protocol use ZM ODEM if it s available to you If you use memory resident programs TSRs Terminate and Stay Resident programs or disk caching programs they may be interfering Try disabling them before you run your communications software Problems that Occur After Connecting 15 5 Mainframe computer keeps dropping your connection You must turn off the Business M odem s result codes and character echo ATQ1E0 The modem a
29. Sets in 10 millisecond units the length of breaks sent from the Business M odem to the computer or terminal Applies to ARQ mode only 22 17 Stores the ASCII code for the XON character 23 19 Stores the ASCII code for the XOFF character 924 150 Sets the duration in 20 millisecond units between pulsed DSR signals when the Business M odem is set to amp S2 or amp S3 The default is 3 seconds 25 Sets DTR recognition time in 10 millisecond units 927 Bit mapped register See the beginning of this appendixfor information about setting bit mapped registers Bit Value Result 0 1 Enable ITU T V 21 modulation at 300 bps for overseas calls In V 21 mode the Business Modem answers both Bell 103 and V 21 calls but only originates V 21 calls 1 2 Enable unencoded non trelliscoded modulation in V 32 mode this option is part of the ITU T V 32 recommendation but is rarely used 2 4 Disable V 32 modulation used for testing HST modulation 3 8 Disable 2100 Hz answer tone to allow two V 42 devices to connect more quickly 4 16 See next page 5 32 See next page 6 48 Disable V 42 Detect Phase 7 128 Unusual software incompatibility Some software may not accept some result codes This setting disables the codes and displays the 9600 code instead The call s actual rate can be viewed on the ATI6 screen Register Default Function Error control handshaking options Select the total value of bits 4 and 5 Bit
30. Speed You can use the amp N and amp U commands to control link speeds Use the following table to determine how to use amp N and amp U commands To limit the Use Highest possible connect speed AT amp N Lowest possible connect speed AT amp U Range of possible connect speeds AT amp N and AT amp U The default values for amp N and amp U are 0 If you change these values you will limit the speeds at which you can connect 3Com recommends that you do not alter these values The amp N command when used in conjunction with the amp U command allows you to limit the highest possible connect speed If a remote modem attempts to connect to your Business M odem at a speed higher than amp N your Business M odem will not allow it to connect To limit the Use this command Where x is Highest possible connect AT amp N x A value from 0 to 32 speed For a complete list of connect speeds see the table in section amp N and amp U Command Values Limiting the Lowest Possible Connect Speed gt Limiting a Range of Possible Connect Speeds gt Controlling Link Speeds with amp N and amp U 8 5 The amp U command allows you to limit the lowest possible connect speed If a remote modem attempts to connect to your Business M odem at a speed lower than amp U your Business M odem will not allow it to connect To limit the Use this command Where x is Lowest possible connect AT amp U x A value from 0 to 32 spe
31. The Business M odem that will be accessed and controlled by other devices Guest The device that will access and control the host Business M odem You can configure up to 10 accounts one administrative account for you and nine accounts for guest users The account profiles are stored in the host Business M odem s nonvolatile random access memory NVRAM There are two forms of Dial Security each will be explained later in this chapter m Autopass m Password Prompting 10 2 CHAPTER 10 DIAL SECURITY Setting up Dial Here is a Summary of the steps for setting up Dial Security Security m Set up an account for yourself a Identify your account as the Administrative Account m Set up guest user accounts a Enable local host security m Choose a Dial Security method wm Enable Dial Security m Activate the Dial Security settings 1 Setup an account for yourself Use any of the 40 available accounts numbered 0 39 for your account Use the AT An command to set up user accounts See the figure below for the five fields to concern yourself with The AT An command is automatically written to NVRAM It does not require you to send amp W Prompt user for dialback number y n AT A0 password y y n 5551000 Account number 0 39 Account enabled y n i Specified dialback A command Password 8 characters Dialback enabled y n number up to 37 maximum case ASCII characters sensitive WAR
32. ZIP files a MNP5 compression is disabled for files that are already compressed and 8 bit binary files that appear to modems to be already compressed Disable M NP5 compressing by sending the Business Modem AT amp K3 wm The file transfer is not slowed down by a file transfer protocol Many non text files require a file transfer protocol but the results vary For the best throughput on error controlled connections only and with hardware flow control we recommend the most current version of ZM ODEM file transfer protocol For example certain public domain file transfer protocols have the following effects Public Domain Effects Kermit Newer versions support packets up to 9K and a sliding window design to eliminate turnaround delay With earlier versions however throughput may be severely reduced due to short block lengths possibly under 128 bytes and acknowledgment turnaround time XMODEM Throughput may be reduced if your version uses short block lengths 128 bytes Some versions use larger blocks 1K blocks Throughput is also reduced by overhead error control protocol information YMODEM There is an improvement over XMODEM due to larger block lengths 1K bytes but throughput is still reduced by the protocol s error control overhead The protocols listed above further reduce throughput when an error control connection is established The accuracy of the data is checked both by the file transfer protocol and t
33. a AT amp TO ATS18 specified number of seconds for example ars18 10 When the 10 seconds are up the modem will stop the test automatically and return to Command M ode Send atx to the modem to hang up or send artz to hang up and reset the modem to its defaults gt If you use the S18 test timer but in the process of testing you issue an ATZ command S18 resets to zero and the timer is disabled You cannot store a value for S18 in NVRAM its power on and reset default is always zero Using AT amp T8 This analog loopback option causes the Business M odem to send an internal test pattern to its transmitter and loop it back to the receiver An internal error detector counts any errors and when the test is ended sends the number of errors or 000 no errors to the screen Since you don t type anything during this test and the Business M odem does not send anything to the screen this option verifies only the Business M odem If there are no errors but your problem continues it may be at the computer interface Send aT amp M0 amp N3S14 0 0 to the modem prepare for testing This command disables error control fixes the connection rate at 2400 bps and makes the Business M odem return to command mode when you type Send aters to begin the test The Business M odem enters analog loopback AL mode and sends a CONNECT message The MR status light flashes The V Everyhing then sends its internal test pattern to the transm
34. a remote access session the maximum number of characters between carriage returns is 40 Once you ve gained guest access to a host you can communicate with the host just as if you were entering commands from its attached computer A Remote Configuration Commands Depending on your access privileges you can use the regular set of Business Modem AT commands If you have this access privilege You can use View only Any of the inquiry ATI commands View and Configure Any of the Business Modem commands except those that cannot be used while online for example ATD or ATA You can also use remote configuration commands See the next section for examples CAUTION Be careful not to send arz or atz or you will lose the connection There are special commands that can be used only during a remote access session You can change the host Business M odem s serial port rate by using the AT Bn command To change the host To change the host Business Modem s Business Modem s serial port rate to Command serial port rate to Command 110 bps AT BO 9600 bps AT B6 300 bps AT B1 19200 bps AT B7 600 bps AT B2 38400 bps AT B8 1200 bps AT B3 57600 bps AT B9 2400 bps ATSBA 115200 bps AT B10 4800 bps AT SB5 Example Sending ars86 will change the Business M odem s serial port rate to 9600 bps 9 6 CHAPTER 9 ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY You can use the AT Fn command to control the dat
35. atst3 to the modem to enter Digital Loopback mode Have the remote user type a short message It will be looped back by your Business M odem s transmitter for verification on the remote user s screen You will not see the message or any other data When the remote user has completed the test send the escape code and then AT amp TO to end the test Alternatively you can end the test by sending ATH or ATZ Be careful because ATZ resets the modem in addition to ending the test In any case the Business M odem responds OK If the modem sends an ERROR message you have issued an invalid command Send at m4 unless you used ATZ Remote Digital Loopback Testing AT amp T6 AT amp T7 Granting a Digital Loopback Test Request AT amp T4 Canceling All Digital Loopback Test Requests amp T5 Transmitter Transmitter TX X gt gt TY am 4x 4 To DTE Telco Telco To DTE __ RX x Receiver PEPA Nook Receiver Pw The remote digital loopback test verifies the condition of both devices and of the phone line Data flow is shown in the figure below Local Remote Data Flow During Remote Digital Loopback The request for and granting of remote digital loopback testing requires that both devices use ITU T V 22 standard signaling If the remote device does not have the capability or is not set to respond
36. either bits or decimal values While it may be simpler for you to set the bits individually your modem displays the S Register settings in decimal form Using Bits Turning individual bits on and off is the more direct way to set bit mapped S Registers To do this specify the S Register that you want to set and then indicate which bits you want to turn on 1 or off 0 Example arsi3 0 1 4 1 5 1 turns bits 0 4 and 5 on for S Register 13 Using Decimal Values An alternative way to set bit mapped S Registers is by adding the decimal values of the bits and entering the total This example ars13 49 sets the same value as the one in Using Bits above Default S Register Settings The table below lists all default values for S Register settings NVRAM Default S Registers Function Setting S0 Auto Answer 0 S1 Counts amp stores rings from incoming 0 calls S2 Escape code character 43 3 Carriage Return character 13 S4 Line Feed character 10 S5 Backspace character 8 S7 Carrier wait time sec 60 S8 Dial pause sec 2 S9 Carrier Detect time 100 ms 6 10 Carrier loss wait time 100 ms 7 S11 Tone duration spacing ms 70 S12 Escape code guard time 500 ms 50 S13 Bit mapped functions 0 S14 Bit mapped functions 0 S15 Bit mapped functions 0 S16 Test modes 0 S18 amp T test timeout 0 S19 Inactivity hang up timer 0 APPENDIX A S REGISTERS NVRAM Default
37. enabled If more than one ring type is enabled the Business M odem will recognize only the enabled ring types and ignore the others When a call arrives the Business M odem will send its ring type in the result code for example RING C Verbal Numeric RING A 170 RING B 171 RING C 172 RING D 173 oe ete e e e WORKING WITH MEMORY This chapter contains information about m Saving a phone number to NVRAM m Working with Flash Memory You can upgrade the software held in Flash memory by performing a software download See Chapter 3 Upgrading your Software for more information about performing a software downloads Overview Business M odems contain three types of memory that you can interact with random access memory RAM nonvolatile random access memory NVRAM and Flash memory Memory type Applies to Loss of power will Command RAM The current settings Cancel any changes you ATI4 make To save settings before resetting the modem use amp W See the section Working with RAM for more detailed information NVRAM Saved settings any NOT affect your settings ATI5 configurations you can store retrieve and change Flash Three templates of NOT affect your settings Not permanent settings You can retrieve the applicable the Business permanent settings and Modem s operating save them to NVRAM but software you cannot alter them 5 2 CHAPTER 5 WORKING WITH ME
38. first of a family of error control software protocols used to transfer files between modems These protocols are in the public domain and are available from many bulletin board services Standard ASCII control characters used to tell a device to stop resume transmitting data In most systems typing lt Ctrl gt S sends the XOFF character Some devices including the Business M odem understand lt Ctrl gt Q as XON others interpret the pressing of any key after Ctrl7 S as XON An error correcting file transfer protocol that is related to but faster than XM ODEM An error correcting file transfer protocol that is related to but faster than XM ODEM or YMODEM 14 GLOSSARY
39. ln Received data software flow XON OFF control amp IO Disables XON XOFF flow control of received data amp ll The modem acts on your typed XON XOFF commands Ctrl S or Ctrl Q and passes them to the remote device amp l2 The modem acts on your XON XOFF commands but removes them from the data stream instead of passing them to the remote device This is the recommended setting for ARQ mode amp l3 Hewlett Packard Host mode Applies only to modems attached to an HP mainframe that uses the ENQ ACK protocol Use in ARQ mode only amp l4 Hewlett Packard Terminal mode Applies only to modems attached to terminals in an HP system that uses the ENQ ACK protocol Use in ARQ mode only amp l5 This setting is designed to enable flow control on the phone link when the connection is not under error control For this to work the remote device must have amp I5 capability amp Kn Enable or disable data compression amp KO Disable data compression amp K1 Use auto enable disable The modem enables compression if the serial port rate is fixed amp B1 and disables compression if the serial port rate follows the connection rate amp B0 because compression offers no throughput advantage when the serial port and connection rates are equal in fact compression may degrade throughput amp K2 Always enable data compression B 8 APPENDIX B ALPHABETIC COMMAND SUMMARY Command Function amp K3 Selective data compressi
40. modem at 2400 bps or less it may not support error control Try sending AT amp M 0 and then try the call again Reset the Business M odem send ATZ after you finish the call Hear ringing but the Business Modem won t answer m Lookatthe TR LED to make sure that your terminal or computer is sending a DTR signal via the EIA 232 interface m Send ATI4 to the Business Modem and check that SO is set to a value higher than 0 m Set amp F1 and SO 1 then try again The Business M odem acts as though a data link has been established but no call was received Carrier Detect CD may be overridden with amp CO but your system may require that the override be turned OFF with amp C1 Review your communications software manual to see what CD operations are required The Business M odem behaves as if Enter were pressed when you don t press any keys Your software may be misreading signals from the Business M odem when the Business M odem sends a Carriage Return and a Line Feed before and after the RING and CONNECT messages Sending the Quiet mode command ATQ1 should solve the problem Problems that Occur After Connecting Your screen displays random or garbage characters M ake sure that the Business M odem is set to the same bit rate word length parity and number of Stop bits as the device to which you are connecting If the settings are correct the problem may be with the phone line Try the following measures
41. the data flow on the other The result is more efficient line operation While most modems on the market now use higher speeds there may be a problem in answering older V 32 modems at 9600 bps Use Register 28 to modify the duration of the extra tones used in V 32 negotiations in the rare instance that this may be necessary See Appendix A S Registers Error Control p Error Control Commands Business M odems can employ error control techniques during data connections High speed data calls are vulnerable to errors unless the data is protected by error control If your Business M odem connects with a remote device at a high speed but without error control and if you are not using an error control protocol for your call you may lose data Automatic Repeat Request ARQ is a method used in many error control protocols to ensure that any data that has been corrupted in transit is retransmitted We use the term to designate a connection under error control You can use Error Control commands to enable ARQ error control The Business M odem and the remote device must use the same protocol For your modem to Command Have no error control Normal M ode AT amp MO Due to the nature of phone line channels this is never recommended for analog calls above 2400 bps Operate in Normal mode if an ARQ connection can t be AT amp M4 made Normal ARQ mode Hangs up if it can t make an ARQ connection ARQ AT amp M5 A
42. to NVRAM with amp W or forced with C2 96 C2 Force configuration changes to take effect immediately We recommend against forcing configuration changes unless it is absolutely necessary An unreliable connection or loss of connection may result Command Function 96 E n Erase security settings 96 E 1 Erase local access password 9o E 2 Erase Autopass password 96 E23 Erase passwords in accounts 0 9 96 E24 Erase phone numbers in accounts 0 9 96 E 5 Disable Account Dialback and New Number fields in accounts 0 9 Command Function Fn Remotely configure another device s data format FO No parity 8 data bits F1 Mark parity 7 data bits F2 Odd parity 7 data bits F3 Even parity 7 data bits L Set a local access password Pn Disable password security n 0 or n 1 when no character follows the equal sign Pn s Set the following password s for viewing privileges only n 0 or view and configuration privileges n 1 Pn Display password n S n Access the security accounts Does not disable security 96 T Enable the recognition of tone frequencies of analog dialing devices T is meant primarily for use with network applications but may also be integrated into certain software programs For example T could be used in a security program to identify incoming tone security codes To return the modem to Command mode press any key
43. will be created in the Dial Up Networking Window Move your cursor to the new icon you have just created and click the right mouse button Select Properties on the menu to display the following window The following screen may vary slightly depending on the version of Windows 95 98 you are using Windows 95 98 1 5 teen ee Hy Connection My Connection a mz 0 0 00 0 United States of America 1 7 3Com OfficeConnect 56K Business Modem Y 9 On the My Connection window click Server Type and deselect the following Logon to Network NetBEUI m IPX SPX Compatible 1 6 CHAPTER 1 CONNECTING TO YOUR ISP 10 Click OK and OK If your ISP Do this Gives you a specific IP Go to Step Four Customizing TCP IP Settings or Domain Name server addresses Does not give you a Double click on the icon you just created to dial your ISP specific IP or Domain Name server addresses Step Four Customizing the TCP IP Settings Depending on the ISP you use you may need to customize the TCP IP settings Follow steps 1 6 and if you still cannot connect to your ISP contact you can contact your ISP for specific information such as an IP address or Domain Name Servers DNS 1 Double click My Computer and double click Dial Up Networking to display all the connections you can customize 2 Right click the icon you created and select Properties to display the My Connection properties window 3 On the My Conne
44. 26 41333 27 42666 28 44000 29 45333 30 Link Speed Index 46666 31 48000 32 49333 33 50666 34 52000 35 53333 36 54666 37 56000 38 57333 39 Setting DTE Rate to 230 Kbps gt The DTE rate of your Business M odem has been increased to 230 kbps to enhance throughput This command is only supported on Business M odems attached to high speed serial cards 8 8 CHAPTER 8 CONTROLLING DATA RATES eee e e e ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY This chapter contains information about m Setting up remote access m Accessing the host m Quitting a remote access session Overview You can set up the Business M odem so other devices can view or change its configuration remotely You should be familiar with these terms before you continue Local The device that is directly connected to the computer you are using Remote The device at the other end of a telephone connection Host The Business M odem that will be accessed and controlled by other devices Guest The device that will access and control the host Business M odem Setting Up Remote Access At the Host Business Modem 1 Prepare to send AT commands by putting your communications software in Terminal Mode 9 2 CHAPTER 9 ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY gt 2 Enable remote access Set Register S41 for a value of 1 or greater S41 sets
45. 48 72 73 74 96 121 122 145 146 FTH n Transmit HDLC data with carrier 3 24 48 72 73 74 96 121 122 145 146 FRH n Receive HDLC data with carrier 3 24 48 72 73 74 96 121 122 145 146 FAX Service Class 2 0 Commands In addition to the standard Class 2 0 fax commands 3Com implements the following optional Class 2 0 fax commands FNS 0 1 Pass through nonstandard negotiation byte string FCR 0 1 Capability to receive FAA 0 1 Adaptive Answer mode FCT 0 255 sec Phase C Timeout FHS 0 255 Hangup Status Code read only FM S 0 3 Minimum Phase C Speed FBS 500 100 Buffer size read only G 2 APPENDIX G FAX INFORMATION FOR PROGRAM MERS Fax Mode Flow Control Setting M any facsimile software products use software flow control when the modem is in Fax mode Throughout our documentation we recommend that you use hardware flow control for Data mode factory setting However to allow compatibility with software products that use software flow control by default 3Com fax modems automatically change to software flow control when entering Fax mode FCC Notice FCC part 68 rules regarding fax operation has been amended as follows Telephone facsimile machines identification of the sender of the message It shall be unlawful for any person within the United States to use a computer or other electronic device to send any message via a telephone facsimile machine unless such a message clear
46. 4800 bps V 32 modems fall back to 4800 bps when line quality is impaired and fall forward again to 9600 bps when line quality improves An ITU T standard that extends the V 32 connection range 4800 7200 9600 12K and 14 4 Kbps V 32 bis modems fall back to the next lower V 32 terbo V 34 V 35 V 42 V 42 bis V Fast Class V FC word length XMODEM XON XOFF YMODEM ZMODEM GLOSSARY 13 speed when line quality is impaired and fall back further as necessary They fall forward to the next higher speed when line quality improves Modulation scheme that extends the V 32 connection range 4800 7200 9600 12K 14 4K 16 8K 19 2K and 21 6 Kbps V 32 terbo modems fall back to the next lower speed when line quality is impaired and fall back further as necessary They fall forward to the next higher speed when line quality improves An ITU T standard that allows data rates as high as 28 8 Kbps An ITU T standard trunk interface between a device and a packet network using signaling of at least 19200 bps An ITU T standard for modem communications that defines a two stage process of detection for LAPM error control An extension of ITU T V 42 that defines a specific data compression scheme for use with V 42 error control Proprietary modulation scheme developed by Rockwell International for data communication speeds up to 28 8 Kbps The number of bits in a data character without parity start or stop bits The
47. 4si6 o to the modem eee e t e TROUBLESHOOTING This chapter explains how to troubleshoot the Business M odem This chapter is divided into these sections m Problems that occur before connecting m Problems that occur after connecting a What to do if you still have problems Problems That Occur Before Connecting No response to AT For Windows users make sure that you set the correct COM port and IRQ in your communications software and if applicable in Windows Control Panel Ports For M acintosh users make sure that you set the correct serial port modem port or printer port and that AppleTalk is disabled a Make sure that your communications software is in Terminal mode m Besurethat your communications software is set to the correct bit rate and word length 7 bits with or without a parity bit or 8 bits and no parity 15 2 CHAPTER 15 TROUBLESHOOTING m Make sure that verbal result codes status messages are enabled Send these commands to the Business Modem For your modem to Command enable message display ATQO Display verbal messages ATV1 a Review your communications software manual to see what Carrier Detect CD operations your software requires Then see the chapter about Controlling EIA 232 Signaling m Although it is a rare condition check whether your computer is reversing the send receive functions at the EIA 232 interface Refer to your computer s documentation
48. BEL 39 27 71 47 G 103 67 g 08 08 BS 40 28 72 48 H 104 68 h 09 09 HT 41 29 73 49 105 69 l 10 0A LF 42 2A 74 4A J 106 6A j 11 0B VT 43 2B t 75 4B K 107 6B k 12 0C FF 44 2C 76 4C L 108 6C 13 0D CR 45 2D 77 4D M 109 6D m 14 OE SO 46 2E 78 4E N 110 6E n 15 OF SI 47 2F 79 4F 0 111 6F o 16 10 DLE 48 30 0 80 50 P 112 70 p 17 11 XON 49 31 T 81 51 Q 113 71 q 18 12 DC2 50 32 2 82 52 R 114 72 r 19 13 XOF 51 33 3 83 53 S 115 73 S 20 14 DC4 52 34 4 84 54 T 116 74 t 21 15 NAK 53 35 5 85 55 U 117 75 u 22 16 SYN 54 36 6 86 56 V 118 76 v 23 17 ETB 55 37 7 87 57 W 119 77 w F 2 APPENDIX F ASCII CHART Dec Hex Char Dec Hex Char Dec Hex Char Dec Hex Char 24 18 CAN 56 38 8 88 58 X 120 78 x 25 19 EM 57 39 9 89 59 Y 121 79 y 26 1A SUB 58 3A 90 5A Z 122 7A z 27 1B ESC 59 3B i 91 5B 123 7B 28 1C FS 60 3C lt 92 5C 124 7C 29 1D GS 61 3D 93 5D 125 7D 30 1E RS 62 3E gt 94 5E a 126 7E 31 1F US 63 3F 95 5F 127 7F DEL eeee e e ecee FAX INFORMATION FOR PROGRAMMERS Fax Service Class 1 Commands FCLASS What mode is in use Data or Fax FCLASS n 0 1 2 0 Class identification and control FCLASS What Fax class is in use FTS n 0 255 Stop transmission and pause 10 ms FRS n 0 255 Wait for silence 10 ms FTM n Transmit data with carrier 3 24 48 72 73 74 96 121 122 145 146 FRM n Receive data with carrier 3 24
49. Com 3Com OfficeConnect 3 56K Business Modem Command Reference http w w w 3com com Published January 1999 3Com Corporation 3800 Golf Rd Rolling Meadows Illinois 60008 Copyright 1999 3Com Corporation All rights reserved No part of this documentation may be reproduced in any form or by any means or used to make any derivative work such as translation transformation or adaptation without written permission from 3Com Corporation 3Com Corporation reserves the right to revise this documentation and to make changes in content from time to time without obligation on the part of 3Com Corporation to provide notification of such revision or change 3Com Corporation provides this documentation without warranty term or condition of any kind either implied or expressed including but not limited to the implied warranties terms or conditions of merchantability satisfactory quality and fitness for a particular purpose 3Com may make improvements or changes in the product s and or the program s described in this documentation at any time If there is any software on removable media described in this documentation it is furnished under a license agreement included with the product as a separate document in the hard copy documentation or on the removable media in a directory file named LICENSE TXT or LICENSE TXT If you are unable to locate a copy please contact 3Com and a copy will be provided to you UNITED STATES G
50. Com before the later of April 1 2000 or ninety 90 days after purchase of the product from 3Com or its authorized reseller 3Com shall at its option and expense provide a software update which would effect the proper performance of such product repair such product deliver to Customer an equivalent product to replace such product or if none of the foregoing is feasible refund to Customer the purchase price paid for such product Any software update or replaced or repaired product will carry a Year 2000 Warranty for ninety 90 days after purchase or until April 1 2000 whichever is later OBTAINING WARRANTY SERVICE Customer must contact a 3Com Corporate Service Center or an Authorized 3Com Service Center within the applicable warranty period to obtain warranty service authorization Dated proof of purchase from 3Com or its authorized reseller may be required Products returned to 3Com s Corporate Service Center must be pre authorized by 3Com with a Service Repair Order SRO number marked on the outside of the package and sent prepaid and packaged appropriately for safe shipment and it is recommended that they be insured or sent by a method that provides for tracking of the package The repaired or replaced item will be shipped to Customer at 3Com s expense not later than thirty 30 days after 3Com receives the defective product Return the product to 3Com Client SROZ 1800 W Central Ave Mt Prospect IL 60056 3Co
51. DSR signal to your computer when it is ready to send and receive data CAUTION Do not change the default setting of amp SO unless you know that your installation requires a different setting Few Windows communications programs if any will require the Business Modem to control DSR amp S1 Use the following command to control how the modem sends the DSR signal For you modem Command To send the DSR signal at all times AT amp SO Default When originating a call to send the DSR signal after dialing AT amp S1 when the Business M odem detects the remote analog device s answer tone When answering a call to send DSR after the Business Modem AT amp S1 sends its answer tone After sending Carrier Detect CD to send a pulsed DSR signal AT amp S2 followed by a Clear to Send CTS signal Use this option for specialized equipment such as automatic callback units After sending Carrier Detect CD to send a pulsed DSR signal AT amp S3 To send a DSR signal to your computer at the same time the AT amp S4 Business Modem sends the CD signal To send DSR normally with CTS after sending CD AT amp S5 In order to change the DSR pulse time in 20 second increments set S Register 24 See Appendix B Alphabetic Command Summary Example Issuing arss3 configures the Business Modem to send a pulsed DSR signal after sending the Carrier Detect CD signal Carrier Detect 7 3 Carrier Detect Carrier
52. If the remote device doesn t recognize an M NP Link Request error control isn t possible In HST asymmetrical mode 3Com devices use a proprietary scheme similar to M NP Flow control of data from the computer is required under error control for two reasons m The transmitting device buffers a copy of each frame it transmits to the remote end until it is acknowledged by the receiving device m f errors are encountered retransmission activity can cause a steady stream of data from the computer to overflow the buffer 12 8 CHAPTER 12 HANDSHAKING ERROR CONTROL DATA COMPRESSION AND THROUGHPUT Data Compression V 42bis versus MNP5 Data Compression Business Modems employ different data compression techniques during data connections For the modem to Command Disable data compression AT amp KO Auto enable disable data compression The Business AT amp K1 Default Modem enables compression if the serial port rate is fixed amp B1 and disables compression if the serial port rate follows the connection rate amp BO Always enable data compression AT amp K2 Selective data compression Use this setting to transfer AT amp K3 compressed files The Business M odem negotiates only for V 42bis compression and disables M NP Level 5 M NP5 compression Example Sending av xs3 is used to transfer compressed files The modem will only negotiate for V 42bis compression This command also will disable M NP Level
53. L TEMPLATE Hardware Flow Control Software Flow control No Flow Control RESULT CODE MEANINGS AND SETS Result Code M eanings Result Codes Sets for Xn Values TECHNICAL INFORMATION Technical Specifications Modulation Additional Specifications Serial Ports The EIA 232 Interface Wiring a DB 25 to DB 9 Cable Minimum Requirements Flow Control Requirements For Macintosh Computers G FAX INFORMATION FOR PROGRAMMERS Fax Service Class 1 Commands FAX Service Class 2 0 Commands Fax Mode Flow Control Setting FCC Notice S REGISTERS S Registers J WARRANTY 3Com Corporation Limited Warranty Notices FCC Certification Statement FCC Registration FCC Notice FCC Notice Radio and Television Interference IC Industry Canada UL Listed Accessory GLOSSARY ABOUT THIS GUIDE Introduction gt This guide is a command reference for the 3Com OfficeConnect 56K Business Modem It includes information about AT commands S Registers and troubleshooting If the information in the release notes shipped with your product differs from the information in this guide follow the instructions in the release notes Finding Specific Information in This Guide This table shows the location of specific information in this guide If you are looking for information about Turn to Connecting to your ISP Chapter 1 Upgrading Your Busniess Modem Chapter 3 Basic AT Commands Chapter 2
54. M Set your software to the desired word length parity and serial port rate defaults before sending the modem the AT amp W string No Flow Control The table below lists the No flow control template To load this template send aTsrFo to the modem NVRAM Options Setting Description Handshake option BO ITU T answer sequence Transmitter Cl Enabled Command mode echo E1 Enabled Online local echo F1 Disabled Training tone volume L2 Medium Speaker control M1 ON during dial through connect Result codes Q0 Enabled Verbal or numeric V1 Verbal result codes result codes Result code subset X1 Basic Protocol response amp A3 Full protocol codes codes Serial port rate select amp B1 Serial port rate fixed higher than connect rate Carrier Detect amp C1 Normal operations Guard tone amp G0 U S Canada Transmit data amp HO Disabled hardware flow control No Flow Control C 5 NVRAM Options Setting Description Record data software amp l0 Disabled flow control Analog data amp K1 Enabled compression Normal lines amp LO Normal lines Error control amp M4 Normal error control Link rate select amp NO Variable Record data hardware amp R1 Disabled flow control Data Set Ready amp S0 Always on Remote Digital amp T5 Deny RDL Loopback RDL Break handling amp Y1 Clear buffer send immediately Stored telephone amp Z0 9 0 Blank
55. MORY gt Working with RAM and NVRAM gt Example Sending avz5 will display NVRAM settings on your screen To see a complete listing of the permanent settings stored in Flash memory see Appendix C Flow Control Templates You can change any setting just for the current session For example setting your Business Modem to arens will only allow a connection to a remote devices at a rate of 14400 bps until the modem is reset Once the modem is reset the default variable connection rate will be re established If you want the new setting to be a default write it to NVRAM at the same time From the example above you would send arsensew to the modem The new default setting for your Business M odem will only allow a 14400 bps connection to a remote device To restore NVRAM factory defaults use the AT amp Fn command See Appendix B Alphabetic Command Summary for more information on setting amp Fn Saving a Phone Number to NVRAM For your modem to Command Write the phone number s to a position n in memory You can AT amp Zn s store up to 10 phone numbers of up to 40 characters each in positions 0 9 Display the number stored in the last dialed number buffer ATDL Display the phone number stored in NVRAM at position n where AT amp Zzn n 0 9 CAUTION Do not include modem commands in AT amp znss Example To store the phone number 555 6789 at position 2 type AT amp Z2 555 6789 If you want to dial the
56. NING Do not insert spaces between commas or between fields and commas Spaces will invalidate the command Dialback options p Setting up Dial Security 10 3 You can set the Business M odem to automatically dialback a certain number after a client modem dials in Count your commas There should always be four commas in the 96A command Do not insert spaces between commas or between fields and commas Spaces will invalidate the command To make the host Business Modem Command Example Hang up and then dial backa AT SAO password y AT AO corn y y n 1 8 guest device at a specified Y n 1 area code 475555555 number and phone number Expect a pause of approximately 1 5 minutes before the modem dials back You cannot alter the duration of the pause Prompt you to enter a ATSAO0 password y AT AQ corn y y y number at which to dialback y y a device and then have the Business M odem dialback the device at that number Disable dialback AT AO0 password y AT AO0 corn y n n L To enable Dialback you must enable Dial Security with Prompting See step 6 Identify your account as the Administrative Account For your modem to Command Example Identify your account asthe AT L ATSL PW0 Administrative Account This example sets account 0 as the Administrative Account Once you set the administrative password you cannot view or modify the guest account profiles unless you enter the correct administrati
57. OVERNMENT LEGEND If you are a United States government agency then this documentation and the software described herein are provided to you subject to the following All technical data and computer software are commercial in nature and developed solely at private expense Software is delivered as Commercial Computer Software as defined in DFARS 252 227 7014 June 1995 or as a commercial item as defined in FAR 2 101 a and as such is provided with only such rights as are provided in 3Com s standard commercial license for the Software Technical data is provided with limited rights only as provided in DFAR 252 227 7015 Nov 1995 or FAR 52 227 14 June 1987 whichever is applicable You agree not to remove or deface any portion of any legend provided on any licensed program or documentation contained in or delivered to you in conjunction with this User Guide Portions of this documentation are reproduced in whole or in part with permission from as appropriate Unless otherwise indicated 3Com registered trademarks are registered in the United States and may or may not be registered in other countries 3Com the 3Com logo U S Robotics and OfficeConnect are registered trademarks of 3Com Corporation 3ComFacts is a service mark of 3Com Corporation Artisoft and LANtastic are registered trademarks of Artisoft Inc Banyan and VINES are registered trademarks of Banyan Systems Incorporated CompuServe is a registered trademark of CompuServe
58. Play most installations are trouble free You must power on your modem before you start Windows 95 98 or Windows 95 98 will not recognize your modem You need Windows 95 98 with Dial Up Networking installed to configure your modem for Windows 95 98 Plug and Play mode allows Windows 95 98 to automatically detect your modem and determine which modem configuration file called an INF file to use Follow the steps below to install the INF file for Windows 95 98 Power on your computer and start Windows 95 98 Your computer will detect new hardware When the New Hardware Found window appears select Driver from disk provided by hardware manufacturer and click OK This step will install the INF file that is provided on the Connections CD ROM 1 2 CHAPTER 1 CONNECTING TO YOUR ISP 3 When the following window appears insert your Connections CD ROM change the default drive in Copy Manufacturer s files from to p or the correct path of your CD ROM and click OK to install the INF file cs Insert the manufacturer s installation disk into the drive selected and then click OK Cancel Copy manufacturer s files from m yg Browse 4 Windows 95 98 displays a window asking you to choose your modem type from the list Select the your modem from the list and click OK Your modem is now ready to use Files Needed By Your For your modem to work most efficiently 3Com recommends that you modem _ use the latest ve
59. Reset when DTR drops 1 2 Reverse normal Auto Answer operation On incoming RING enter Originate M ode and look for an answer tone 2 4 Disable 250 ms pause before result code display 3 8 On DTR signal autodial the number stored in NVRAM at position 0 4 16 At power on reset autodial number stored in NVRAM at position 0 5 32 Disable HST used for testing V 32terbo in Business Modems 6 64 Disable M NP Level 3 used for testing Level 2 7 128 Hardware reset works like powering off and then on S14 1 Bit mapped register See the beginning of this appendix for information about setting bit mapped registers Bit Value Result 0 1 Disconnect on escape code S15 0 Bit mapped register See the beginning of this appendix for information about setting bit mapped registers Bit Value Result 0 1 Disable the Business M odem s extra high frequency equalization if it causes problems on shorter link calls for HST modulation only 1 2 Disable online fallback 2 4 Disable 450 bps back channel HST only 3 8 Reset non ARQ mode Transmit buffer from 1 5K bytes to 128 for the convenience of BBS operators taking calls from remote users of slower modems Register Default Function 4 16 Disable M NP Level 4 retransmitting the larger Level 4 data blocks may be a problem if you expect a great number of errors during a call 32 Set Backspace key to delete 64 Some earlier 2400 bps MNP modems not made by 3Com or Microc
60. USE OR BY ACCIDENT FIRE LIGHTNING OTHER HAZARDS OR ACTS OF GOD LIM ITATION OF LIABILITY TO THE FULL EXTENT ALLOW ED BY LAW 3COM ALSO EXCLUDES FOR ITSELF AND ITS SUPPLIERS ANY LIABILITY WHETHER BASED IN CONTRACT OR TORT INCLUDING NEGLIGENCE FOR INCIDENTAL CONSEQUENTIAL INDIRECT SPECIAL OR PUNITIVE DAM AGES OF ANY KIND OR FOR LOSS OF REVENUE OR PROFITS LOSS OF BUSINESS LOSS OF INFORM ATION OR DATA OR OTHER FINANCIAL LOSS ARISING OUT OF OR IN CONNECTION WITH THE SALE INSTALLATION MAINTENANCE USE PERFORM ANCE FAILURE OR INTERRUPTION OF ITS PRODUCTS EVEN IF 3COM OR ITS AUTHORIZED RESELLER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES AND LIMITS ITS LIABILITY TO REPAIR REPLACEM ENT OR REFUND OF THE PURCHASE PRICE PAID AT 3COM S OPTION THIS DISCLAIM ER OF LIABILITY FOR DAMAGES WILL NOT BE AFFECTED IF ANY REM EDY PROVIDED HEREIN SHALL FAIL OF ITS ESSENTIAL PURPOSE DISCLAIM ER Some countries states or provinces do not allow the exclusion or limitation of implied warranties or the limitation of incidental or consequential damages for certain products supplied to consumers or the limitation of liability for personal injury so the above limitations and exclusions may be limited in their application to you When the implied warranties are not allowed to be excluded in their entirety they will be limited to the duration of the applicable written warranty This warranty gives you specific legal rights which may vary dep
61. When using the AT S command the device echoes the administrative password which is case sensitive Business M odems will accept an invalid password entry but will lock out users from the security commands For example if the password is Green but you enter GREEN an OK is displayed However if you try to type a security command for example ATI10 to view accounts an ACCESS DENIED message is displayed Dial Security accounts may be configured remotely See Configuring Dial Security Remotely at the end of this chapter 10 8 CHAPTER 10 DIAL SECURITY What the Guest User Needs to Do A When guest users want to call in to the host assuming you have enabled Dial Security by entering ars53 0 1 m They must know the password m If you have enabled Dialback they must set their device to auto answ er If the host has security enabled get a password from the host s administrator The password is case sensitive so be sure to copy it correctly If the host has prompting enabled and the host operator enables Dialback for your account skip to Step 3 For guest users with Business M odems a Create a security account using the password the host s administrator asked you to use See Setting Up Dial Security earlier in this chapter for instructions b You need to assign the password as your Autopass password For your modem to Command Assign the password as your ATSV PWnh where n is the number of Autopass pas
62. XOFF signaling Use both hardware and software flow control AT amp H3 If you are unsure about what your equipment supports select this option eee e e e HANDSHAKING ERROR CONTROL DATA COMPRESSION AND THROUGHPUT This chapter contains information about m Handshaking m Selective Reject m V 90 Capabilities wm Error Control m Data compression m Getting maximum throughput Handshaking Selective Reject With each call Business Modems go through a link negotiation process with the remote device Another name for the negotiation process is handshaking Business Modems default to V 90 modulation and try for the highest possible speed when they attempt to connect with another modem 56 Kbps If the remote device is not V 34 capable a connection is made using the highest compatible modulation scheme x2 V 34 V FC V 32 terbo V 32 bis and so on down to as low as Bell 103 or 300 bps The Business Modem supports Selective Reject for analog calls Selective Reject improves performance on noisy lines by reducing the amount of overhead incurred when the protocol must resend data due to errors When Selective Reject is active only the frame that contained the error is resent instead of the frame plus all of the following unacknowledged frames 12 2 CHAPTER 12 HANDSHAKING ERROR CONTROL DATA COMPRESSION AND THROUGHPUT Selective Reject is an optional part of the ITU T V 42 LAPM standard
63. a format To change the data format to Command No Parity 8 data bits ATSFO Mark parity 7 data bits ATSF1 Odd Parity 7 data bits ATSF2 Even parity 7 data bits ATSFE3 You can use the AT Cn command to control whether and when to apply changes to the configuration For your modem to Command Defer configuration changes to when the call ATSCO Default ends Restore the original configuration ATSC1 Use this command to cancel any changes made during remote access and restore the original configuration Force configuration changes AT C2 Use this command to make configuration changes take effect immediately We do not recommend forcing changes unless it is absolutely necessary because an unreliable connection or even a loss of connection may result Example Sending arsc1 will cancel any changes made to the modem during a remote access session and restore it to the original configuration Even though by default C0 the changes you make do not take effect until the next connection the new configuration is reflected immediately in inquiry responses ATIn Commands that have been written to NVRAM using amp W and forced configuration changes C2 will not be restored to their previous settings when you send the host AT C1 After you make changes to the host s configuration the remote access prompt changes from Remote gt tO Remotet gt Quitting a Remote Access Session 9 7 If you res
64. ack Disable 450 bps back channel HST only Reset non ARQ mode Transmit buffer from 1 5K bytesto 128 forthe convenience of BBS operators taking calls from remote users of slower modems Disable M NP Level 4 retransmitting the larger Level 4 data blocks may be a problem if you expect a great number of errors during a call Set Backspace key to delete Some earlier 2400 bps M NP modems not made by 3Com U S Robotics or Microcom were not fully compatible with the MNP protocol If you have difficulty making a successful 2400 bps MNP connection with a remote MNP modem it may be because of this incompatibility Set 15 to 64 and try again to make the connection Custom applications only The default 1 5K byte non ARQ buffer allows data transfer with X and Y modem type File Transfer Protocols without using flow control The 128 byte option allows remote users with slower modems to stop your transmitted data from scrolling off their screens When remote users send your computer an XOFF lt Ctrl S gt and you stop transmitting the data in transit doesn t exceed the size of their screen 1 4 APPENDIX S REGISTERS Register Default Function SIO Bit mapped register See Chapter I Using the AT Command Set for instructions on setting bit mapped registers For testing see Chapter 14 Testing Bit Value 2 4 B 8 Result Test pattern Remote digital loopback Test timer for
65. acter Valid range is 0 127 S5 Stores the ASCII decimal code for the Backspace character A value of 128 255 disables the Backspace key s delete function S6 Set the number of seconds the Business M odem waits for a dial tone S7 60 Sets the number of seconds the Business M odem waits for a carrier May be set for much longer duration if for example the Business Modem is originating an international connection S8 Sets the duration in seconds for the pause option in the Dial command and the pause between command reexecutions and A commands S9 Sets the required duration in tenths of a second of the remote device s carrier signal before recognition by the Business Modem S10 14 Sets the duration in tenths of a second that the Business Modem waits after loss of carrier before hanging up This guard time allows the Business Modem to distinguish between a line hit or other disturbance that momentarily breaks the connection from a true disconnect hanging up by the remote device S11 70 Sets the duration and spacing in milliseconds of dialed tones S12 50 Sets the duration in fiftieths of a second of the guard time for the escape code sequence A 6 APPENDIX A S REGISTERS Register Default Function 13 0 Bit mapped register See the beginning of this appendix for information about setting bit mapped registers Bit Value Result 0 1
66. al data transmission and in the case of modems for data reception Data is transmitted one bit at a time serially to devices such as a modem a serial mouse or a serial printer The transfer of data characters one bit at a time sequentially using a single electrical path See Parallel Transmission A form of flow control that uses XON and XOFF characters to start and stop the flow of data The signaling bit attached to the beginning of each character before characters are transmitted during Asynchronous Transmission stop bit shunt S register switch terminal terminal mode throughput transmission rate UART Universal Asynchronous Receiver Transmitter UART UTP Unshielded Twisted Pair V 8 GLOSSARY 11 The signaling bit attached to the end of each character before characters are transmitted during Asynchronous Transmission A small plastic and metal piece used to cover sections of pins on a jumper The shunt interconnects certain pins which depending on the way the shunt is placed determine functions An area of NVRAM that is used to store a setting See central office switch A device whose keyboard and display are used for sending and receiving data over a communications link Differs from a microcomputer in that it has no internal processing capabilities Used to enter data into or retrieve processed data from a system or network An operational mode required for microcomputers to transmit
67. all and the calling party s telephone number Extended service provides the billing name associated with the calling party s telephone number in addition to the Basic service information The information the Business M odem actually receives depends on the service type to which you ve subscribed the information that the calling party s telephone company provides and whether the equipment in between supports caller ID At minimum you will always receive the date and time that a call arrived If a call arrives without a caller ID signal the modem will send OUT OF AREA in place of the phone number and name If the caller ID information has been blocked by the user at the other end the Business M odem will send PRIVATE in place of the phone number and name You can use caller ID to screen calls keep a record of calls or prevent unauthorized access to your network Third party database and telephony applications such as security call logging and black listing applications exploit the caller ID information provided by the Business M odem 4 8 CHAPTER 4 DIALING ANSWERING AND HANGING UP How the Business Modem Handles Caller ID When the modem receives the caller ID signal it stores the information in memory You can access the information at any time by sending arzi5 to the modem atil5 3Com OfficeConnect 56K Business Modem CID Status 801E 01 08 31 30 31 35 32 30 33 38 02 OA 37 30 38 35 35 35 30 30 30 31 07 0C 55 2E 53
68. and which require neither AT nor lt ENTER gt m Leave zeroes off the end of AT commands A missing numeric parameter is assumed to be a zero For example ATE is equivalent to ATEO m Create compound commands of up to 56 characters between AT and ENTER See the following example 2 2 CHAPTER 2 USING THE AT COMMAND SET AT amp K3X2DT5551234 AT Attention a command follows amp K3 Disable M NP5 data compression use only V 42 bis compression X2 Use the X2 result code subset DT Dial the following number using tone dialing Hyphens and parentheses add to the count of 56 characters but spaces do not Basic AT commands The command AT informs the modem that a command is coming AT must precede all commands except A A and To configure your modem to Command Re execute the last issued command A Repeat the last issued command until canceled by pressing A gt any key Example Sending aTp5551234 will make the modem dial 555 1234 Now if you send a the modem will dial 555 1234 again Using S Registers S Registers are addresses of places in memory where various timing parameters redefinitions of selected ASCII characters and other configuration settings are stored Initially the S Register settings for each of the NVRAM templates are the same You can overwrite an S Register s stored value See the default values listed in Appendix A S Registers for a complete listing of the init
69. annel Two types are used fixed compromise equalizers and those that adapt to channel conditions 3Com high speed modems use adaptive equalization error control expansion bus facsimile fax fax mode Flash memory flow control frame file transfer protocol FTP FTP full duplex half duplex handshaking hardware flow control Various techniques which check the reliability of characters parity or blocks of data V 42 MNP and HST error control protocols use error detection CRC and retransmission of errored frames ARQ A series of slots inside a computer that allow for adding feature cards A method for transmitting the image on a printed page from one point to another The mode in which the fax modem is capable of sending and receiving files in a facsimile format A form of memory that can be electrically erased and reprogrammed without the need to remove it from the circuit board A mechanism that compensates for differences in the flow of data input to and output from a modem or other device A data communications term for a block of data with header and trailer information attached The added information usually includes a frame number block size data error check codes and Start End indicators A TCP IP application that allows users of an internet to send put and receive get files See file transfer protocol Signal flow in both directions at the same time In micro computer comm
70. answering a call a Business M odem sending out the Bell answer tone B1 won t be recognized by V protocol modems The calling modem instead will wait until it detects a tone it recognizes The V 22bis tone used at 2400 bps If you want to have your Business M odem connect with V protocol modems at high speeds make sure it is set to BO for the ITU answer tones It will also connect with HST modems at speeds up to 16 8 Kbps On these analog connections Business M odems have two features that result in outstanding performance Quick Connect and Adaptive Speed Leveling ASL a Quick Connect allows two Business Modems to connect in approximately 7 seconds a far shorter time than with most devices m ASL described below in Other V Protocol Operations is used by Business M odems operating in V 32terbo and V 32bis modes Lower speed V Protocols Error Control 12 5 Older lower speed V protocols do not employ line probing Instead they use predefined answer tones to specify or identify speed capabilities These protocols define the following maximum speeds m V 32terbo 19 2 Kbps with an additional USR device to USR device speed of 21 6 Kbps m V 32bis 14 4 Kbps m V 32 V 22bis etc 9600 bps and lower ASL used in V 32terbo and V 32bis modes is a technique that allows the Business M odem s receivers and transmitters to act independently of each other One transceiver may slow down and then speed up without affecting
71. ara to end the test 5 Send atem4 unless you used a reset command ATZ or ATZ 14 10 CHAPTER 14 TESTING THE CONNECTION Testing Using Keyboard Data ATS16 8 1 Send AT amp MO amp N3S14 0 0 to prepare the Business M odem for testing This command disables error control fixes the connection rate at 2400 bps and makes the Business M odem return to command mode when you type the escape code 2 Establish a connection with the remote device 3 If you haven t already done so arrange with the remote user to cooperate with the test If necessary set the remote device to acknowledge the remote digital loopback request 3Com modems should be set to amp T4 Older 3Com modems should be set to S16 8 Send the Business M odem ats16 80 The Business M odem enters remote digital loopback mode and then goes back online O command It then transmits the test signals causing the remote device to enter remote digital loopback mode The MR status light flashes during this operation Type a short message It will be looped back to your Business Modem by the remote device and to your screen for verification The remote user will not see your data Send the escape code and then ATs16 0 to end the test If you issue an invalid command the Business M odem sends an ERROR message If you set Register S18 the Business M odem automatically ends the test when the test timeout is reached See the example in the previous s
72. assword the host sends an INVALID PASSWORD message and hangs up If the guest sends an invalid password the host prompts twice more before disconnecting If the guest does not send a password after 60 seconds the host disconnects If the guest includes a valid password the host permits a secure connection The host will still always respond to a correct Autopass attempt If the guest did not enable Dial Security the host will not accept the call unless prompting is enabled on the host Business Modem 6 Enable Dial Security WARNING Before you enable Dial Security you must set up an administrative account and password See Steps 1 amp 2 For your modem to enable Command Autopass Dial Security ATS53 0 1 Dial Security with Password Prompting ATS53 0 1 1 1 this also enables Autopass Dialback Security enable Password AT An password y y y phone Prompting and enable Dialback in each number guestaccount where n is the account number See the figure in previous section Setting Up Dial Security for more information Example Issuing aT A3 corn y y y 5551234 to your modem will enable Password Prompting and Dialback for account 3 which has the password corn You must use the amp W command to save the settings for Enabling pe Autopass Dial Security and Dial Security with Password Prompting If you don t the next time you reset or power off the Business M odem Dial Security will be d
73. at http www usr com home online in the software library area It can also be downloaded from the BBS at 847 262 6000 After the file is downloaded it needs to uncompressed When the file is uncompressed the USRARA SEA Folder appears Inside the USRARA SEA folder is a readmefirst txt file and the 3Com High Speed script Move the script file to the following path C System Extensions and create a folder named Modem Scripts Once you place the script in the M odem Scripts folder you will have the option to choose the 3Com High Speed in Open Transport PPP or ARA The script will attempt to talk to the modem at 230 4 port speed and if this fails it will attempt at the next lowest speed This will continue until Configuring Open Transport PPP the script receives an OK back from the modem and or the system responds with a proper speed Selecting the correct modem 1 Go to Apple Menu Control Panels Modem 2 Inthe Modems Window choose the port that your modem is connected to in the Connect via drop down box Select the correct modem in the Modem drop down box Connect via Modem Fort US Robotics Universal gt on 3 off Dialing a Tone C3 Pulse Ld Ignore dial tone Macintosh 1 15 Selecting the correct TCP IP settings Go to Apple Menu Control Panel TCP IP In the TCP IP window select PPP in the Connect via drop down box Set the Configure drop down box to Using PPP Server Type in your
74. at Uses the Test Pattern TROUBLESHOOTING Problems That Occur Before Connecting No response to AT The Business Modem won t dial Double characters are appearing on your monitor After you dial the Business Modem reports NO CARRIER and then fonds up 15 3 Hear ringing but the Business Modem won t answer The Business M odem acts as though a data link has been established but no call was received The Business M odem behaves as if lt Enter gt were pressed when you don t press any keys Problems that Occur After Connecting Your screen displays random or garbage characters Many CRC errors Mainframe computer keeps dropping your connection Bad faxes or can t fax Both devices exchange carrier signals but fail to establish a communications link Errors during software download If You Still Have Problems UPGRADING YOUR MODEM Overview Checking Your Business M odem s Software Version Getting New Operating Software Sending New Software to your modem If Your Modem Doesn t Respond S REGISTERS Understanding Bit M apped S Registers How bits are mapped to decimal values Converting Bits to Decimal Values Converting Decimal Values to Bits Setting Bit M apped S Registers Using Bits Using Decimal Values Default S Register Settings A complete list of S Registers ALPHABETIC COMMAND SUMMARY Basic Command Set Ampersand amp Command Set Percent 96 Command Set Octothorpe Command Set FLOW CONTRO
75. bligation under this express warranty shall be at 3Com s option and expense to repair the defective product or part deliver to Customer an equivalent product or part to replace the defective item or if neither of the two foregoing options is reasonably available 3Com may in its sole discretion refund to Customer the purchase price paid for the defective product All products that are replaced will become the property of 3Com Replacement products may be new or reconditioned 3Com warrants any replaced or repaired product or part for ninety 90 days from shipment or the remainder of the initial warranty period whichever is longer YEAR 2000 WARRANTY In addition to the Hardware Warranty stated above 3Com warrants that each product sold or licensed to Customer on and after January 1 1998 that is date sensitive will continue performing properly with regard to such date data on and after January 1 2000 provided that all other products used by Customer in connection or combination with the 3Com product including hardware software and firmware accurately exchange date data with the 3Com product with the exception of those products identified at 3Com s Web site http w w w 3com com products yr2000 html as not meeting this standard If it appears that any product that is stated to meet this standard does not perform properly with regard to such date J 2 APPENDIX J WARRANTY data on and after January 1 2000 and Customer notifies 3
76. ccess the host Follow these steps Be sure that the host device has enabled remote access and is set to auto answer atso 1 Know the password if you will need one Call the host device although it doesn t matter which device originates the call After a connection is established do this a Pause 4 seconds b Type 4 tildes c Pause 4 seconds The administrator of the host device can change the remote access character using S Register 42 and the pause duration using S Register 43 See Appendix A S Registers for more information 9 4 CHAPTER 9 ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY 4 You should see a display similar to this gt gt Viewing and Changing the Host s Configuration 3Com OfficeConnect 56K Business Modem Remote Access Session Serial Number 000000A000000001 Password Ctrl C to cancel There is a 3 minute time limit for entering the password If the number of unsuccessful log in attempts exceeds the set limit the host device returns online and refuses any further log in attempts during the remainder of the connection When the host accepts the password the following message and prompt will appear on your screen Remote Access granted Remote gt You may not be prompted for a password If you aren t password security is not active The following prompt appears on your screen after you type the four tildes Remote Access granted query only Remote During
77. cial instructions for Windows NT users For you to Use this connection Use a dial up connection to connect overthe Serial Line Internet Protocol SLIP Internet SLIP only allows you to connect using IP and does not allow for server assigned IP addresses or server assign name server addresses Use a dial up connection to connect over the Point to Point Protocol PPP Internet PPP allows you to connect using IPX TCP IP Netbeui and other protocols PPP is a more recent development than SLIP and has become the standard way of connecting to the Internet CAUTION Before you use these procedures contact your ISP to determine if they have any special requirements What you need Configuring Your modem gt a uh WYN HB N Windows NT 4 0 and Later 1 9 Before you begin obtain the following information wm Does your ISP have a SLIP or PPP account m Your ISP s telephone number Does your ISP supply a static or dynamic IP address m Your ISP s primary and secondary DNS servers m INF file for Windows NT Since Windows NT is not Plug and Play compliant it is necessary to install the modem in M odem Properties Your modem should already be installed If you have not connected your Business M odem to your computer please refer to the Getting Started M anual for installation instructions Go to Start Settings Control Panel Modems Click Add Check Don t detect my modem I will select it from a list Cli
78. ck Next Click Have Disk Place the diskette or CD ROM that was packaged with your Business M odem into your floppy disk or CD ROM drive Select the INF file found on the disk Select the COM port for your Business M odem 8 When the installation is complete Windows NT will request that you Setting up RAS XO Ui RP U N restart your computer Select yes Right click on the Network Neighborhood icon on your desktop and select Properties Click the Services tab Select Remote Access Service and click Properties Click Add Select your Business M odem s COM port and click OK Highlight your Business M odem and click Configure Select the function of your modem and click OK 10 11 Determining if TCP IP is installed Installing TCP IP Configuring a PPP connection Click Network Select the protocols required to dial in and out with your Business Modem Set Encryption Settings to Allow any authentication including clear text Click Continue to complete RAS setup TCP IP must be installed before you can access the Internet Although this is a standard configuration double check to make sure TCP IP is installed To determine if TCP IP is installed perform the following actions 1 Select Start Settings Control Panel 2 Double click Network 3 On the Protocol tab scan down the list of installed protocols to find TCP IP Protocol Adapter If TCP IP Protocol is listed skip to section Configuring a PPP C
79. command see Appendix B Alphabetic Command Summary before testing If the modem is detecting errors and retransmitting the affected data your results will be invalid Testing the Business Modem using AT amp Tn 14 3 Analog Loopback Local loopback testing checks the operation of the Business Modem Testing transmitter and receiver Transmitter Receiver Using AT amp T1 1 Send arsmosn3s14 0 0 to prepare the modem for testing This command disables error control fixes the connection rate at 2400 bps and makes the modem return to command mode when you type 2 Send arsti to the modem so it enters analog loopback mode The MR status light flashes 3 It will be looped back by your modem s transmitter for verification on your screen 4 When the test is completed send and then arero to end the test Alternatively you can end the test by sending ATH or atz Be careful though because ATZ resets the modem in addition to ending the test In either case the modem responds with OK If the modem sends an ERROR message you have issued an invalid command 5 Send atem4 unless you used a reset command ATZ If the Business M odem is in online mode that is still connected to a p remote modem and you send AT amp T1 or AT amp T8 it drops the call enters analog loopback mode sends a CONNECT result and waits for loopback characters Stopping a Test To stop a test send areto to the modem or set Register S18 to
80. command options Example AT amp Z2 555 6789 In the following example amp M 0 no error control is inserted before the Dial command AT amp MO DS2 This command functions differently when Dial Security is enabled Also do not include modem settings in the amp Zn string If the call requires a special setting insert it in the command string before the DSn command amp Zn L Stores the last dialed number in position n amp Zn Display the phone number stored in NVRAM at position n where n 0 9 amp ZC s Store command string s in NVRAM The command string can be up to 30 characters long spaced do not count This command is used So you can call another modem without loading your communications software amp ZC Display the stored command string Percent 96 Command Set Command Function Display the help panels for the percent command set Command Function An Create and configure security accounts Bn Remotely configure a modem s serial port rate BO 110 bps 96 B1 300 bps 96 B2 600 bps B3 1200 bps 96 B4 2400 bps B5 4800 bps B6 9600 bps 96 B7 19200 bps B8 38400 bps B9 57600 bps 96 B10 115200 bps Cn Remote configuration control CO Defer configuration changes until the call is ended Changes take effect for ensuing connections 96 C1 Cancel configuration changes and restore the original configuration Using96 C1 will not reverse any changes that you wrote
81. correct TCP IP settings Setting up your ISP information Other Operating Systems If You Are Using Windows 3 x If You Are Using MS DOS If You Are Using UNIX Linux or AIX UsiNG THE AT COMMAND SET Overview General rules for using AT commands Basic AT commands Using S Registers Displaying S Register settings Setting an S Register Getting a list of S Registers Understanding bit mapped S Registers MODES OF OPERATION Command and Online M odes Entering Online Command M ode Returning to Online Mode Controlling Local Echo Command M ode Local Echo Online M ode Local Echo Data and Fax M odes DIALING ANSWERING AND HANGING UP Dialing Dial options Carrier Loss Redial Answering Calls Force Answer Mode Auto Answer Hanging up M aking International calls Handshaking options Guard tone Caller ID Functions Service Types Applications of Caller ID Technology WORKING WITH MEMORY Overview Working with RAM and NVRAM Saving a Phone Number to NVRAM Displaying S Register Value Information Saving a Command String to NVRAM Working with Flash Memory Saving ROM Templates to NVRAM Default Settings CONTROLLING RESULT CODE DISPLAYS Result Code Display Commands Additional Result Code Subsets CONTROLLING EIA 232 SIGNALING Data Terminal Ready Data Set Ready Carrier Detect CONTROLLING DATA RATES Overview Serial Port Rates Connection Rates Controlling Link Speeds with amp N and amp U Cont
82. ction is used only in factory testing The Business Modem should always display the same number 13 2 CHAPTER 13 DISPLAYING QUERYING AND HELP SCREENS For your modem to Command Perform a test of the modem s random access memory RAM and display either OK 0 or ERROR 4 followed by OK when the test is completed You may want to use this command if the Business Modem appears to be malfunctioning ATI2 Display the Business M odem s banner or product title ATI3 Display the Business M odem s current configuration ATIA Display the configuration saved in nonvolatile random access memory NVRAM If your Business Modem connects to a device that has Dial Security and local access enabled you cannot view the stored phone numbers ATI5 Display a diagnostic summary During a connection the Business Modem monitors and stores information about link operations When the call is ended you can request a diagnostic summary The duration of the last call or the real time is displayed depending on the modem clock setting For calls under data compression the number of characters sent may be less than the number of octets sent due to data compression operations ATI6 Display the product configuration ATI7 Display the Dial Security Account Status For security administrators only unless local security is disabled S53 0 or S53 2 0 ATI10 Display a connection report that
83. ction properties window click the Server Type tab 4 Click TCP IP Settings Windows 95 98 1 7 TCPAP Settings i x Server assigned IP address C Specify an IP address Primary DNS B 0 0 8 Secondary DNS 0 0 0 0 Primary WINS 0 0 0 0 a ea Secondary WINS ao 0 v Use IP header compression IV Use default gateway on remote network K Cancel 5 Specify an IP address if needed If your ISP Do this Gives you a specific IP Click Specify an IP address and enter the IP address address provided by your ISP Does not give you a Click Server assigned IP address specific IP address 6 After you specify an IP Address specify server assigned name server addresses if needed If your ISP Do this Gives you specific name Click Specify name server addresses and enter the server addresses server address es provided by your ISP Does not give you Click Server assigned server address specific name server addresses 1 8 CHAPTER 1 CONNECTING TO YOUR ISP 7 Double click your New Connection icon to connect Windows NT 4 0 and Later gt A TCP IP is the main protocol used to transfer data via the Internet To use TCP IP with Windows NT you must connect to your ISP using a PPP or SLIP connection Each ISP has different requirements Before using this chapter to configure Windows NT to access your ISP contact your ISP to determine if they have spe
84. d The customer should be aware that compliance with the above conditions may not prevent degradation of service in some situations Repairs to certified equipment should be made by an authorized Canadian maintenance facility designated by the supplier Any repairs or alterations made by a user to this equipment or equipment malfunctions may give the telecommunications company cause to request the user to disconnect the equipment Users should ensure for their own protection that the electrical ground connections of the power utility telephone lines and internal metallic water pipe system if present are connected together This precaution may be particularly important in rural areas CAUTION Users should not attempt to make electrical ground connections by themselves but should contact the appropriate inspection authority or electrician as appropriate Your modem is a UL listed accessory It must be used with a UL listed computer 16550 UART Adaptive Speed Leveling ASL analog signals answer mode application application program ARQ ASCII ASL asymmetrical modulation GLOSSARY The fastest type of UART that is currently available Business Modem V 32 bis and V 32 terbo modems detect improved line conditions and shift upward again to the next higher speed The modems at both ends of the connection adapt independently each detecting and adjusting to line conditions ASL keeps the modems online always op
85. d tone AT amp G1 Some European countries 1800 Hz guard tone AT amp G2 The U K and some Commonwealth countries If you set amp G2 you must also send arso to the modem This setting allows the Business M odem to answer all calls from overseas M ake Break Ratio The AT amp Pn command sets the off hook on hook make break interval for pulse dialing To set you modem for Command North American make break ratio 39 61 AT amp PO United Kingdom make break ratio 33 67 AT amp P1 Call Detection Call Detection allows the modem to recognize whether an incoming call is analog data or fax Call Detection is an optional Service Class 2 0 feature and is also implemented by 3Com for Fax Class 1 applications Caller ID Functions Service Types Applications of Caller ID Technology Caller ID is a service provided by local telephone companies When you subscribe to caller ID your phone company begins providing you real time information about incoming calls The caller ID signal includes the date and time of the call the phone number of the calling device and optionally the name of the calling party The signal is sent between the first and second rings and must be decoded and displayed by a device connected to your phone line The Business M odem has the ability to decode and display the caller ID information You can subscribe to Basic or Extended caller ID service Basic service offers you the date and time of the c
86. data In Terminal mode the computer acts as if it were a standard terminal such as a teletypewriter rather than a data processor Keyboard entries go directly to the modem whether the entry is a modem command or data to be transmitted over the phone lines Received data is output directly to the screen The more popular communications software products control Terminal mode as well as enable more complex operations including file transmission and saving received files The amount of actual user data transmitted per second with out the overhead of protocol information such as Start and Stop bits or frame headers and trailers Compare characters per second See it rate See Universal Asynchronous Receiver Transmitter A computer chip that controls the signaling that goes on through a computer s serial port Twisted insulated copper wires bundled into an unshielded cable commonly used in telephone wiring systems Grades of UTP include DTP Datagrade Twisted Pair and DIW Distributed Inside Wire ITU T recommendation that defines procedures for starting and ending sessions of data transmission 12 GLOSSARY V 17 V 21 Fax V 21 Modem V 22 V 22 bis V 23 V 25 V 25 bis V 27ter V 29 V 32 V 32 bis An ITU T standard for facsimile operations that specifies modulation at 14 4 Kbps with fallback to 12 Kbps An ITU T standard for facsimile operations at 300 bps 3Com or compatible fax devices then transmit or r
87. data is retained when modem power is turned off Used in modems to store a user defined default configuration loaded into random access memory RAM at power on See Non volatile Random Access M emory A feature that allows high speed error control modems to monitor line quality and fall back to the next lower speed if line quality degrades The modems fall forward as line quality improves originate mode parallel transmission parity Plug amp Play ISA Point to Point Protocol PPP protocol provisioning RAM Random Access Memory RAM A state in which the modem transmits at the predefined low frequency of the communications channel and receives at the high frequency The transmit receive frequencies are the reverse of the called modem which is in Answer mode The transfer of data characters using parallel electrical paths for each bit of the character for example 8 paths for 8 bit characters Data is stored in computers in parallel form but may be converted to serial form for certain operations See Serial Transmission An error detection method that checks the validity of a transmitted character Character checking has been surpassed by more reliable and efficient forms of block checking including Xmodem type protocols and the ARQ protocol implemented in modems The same type of parity must be used by two communicating computers or both may omit parity When parity is used a parity bit is added to each trans
88. de you can be sent to the latest firmware web page m Call the 3Com Bulletin Board Service BBS at 847 262 6000 From the main menu select Files a Select area 5 USR Business Modem Download the newest Business M odem file with the extension ZIP Remember to select the proper ZIP file for your Business M odem m f you have problems with downloading the current shipping version of the modems software call 3Com Technical Support at 888 326 6099 Sending New Software to your modem P To send the new code to your modem all you need is a standard terminal program that can send files using the XM ODEM protocol Start a communications software package such as Hyperterminal Quick Link Il or MacComCenter Adjust the settings if necessary so you can send AT to your modem and get an OK response If you are sending the file from a M acintosh computer make sure you do not transfer the file in M acBinary format In MacComCenter for example select Setup File Transfer Under M acBinary options select Never M acBinary Sending New Software to your modem 16 3 2 Enter ar x The modem should respond as follows at x SDL Xmodem file transfer Y es N o T est gt 3 Type t ENTER to start an integrity test of the XMD file Your screen should appear as follows SDL Xmodem file transfer Y es N o T est gt t Test Mode Flash ROM will not be modified Begin Xmodem file transfer now CC Se
89. de Displays and Appendix D Result Code Meanings and Sets If the modem is set to X2 or lower it interprets the W as a two second pause unless it detects a second dial tone within two seconds ATDW CHAPTER 4 DIALING ANSWERING AND HANGING UP Vv For your modem to Command Wait for an answer with X3 or higher Some online services answer the phone and return a tape recorded request for information before processing transactions Use the ATQ command to tell the modem to detect at least one ring wait for five seconds of silence at the other end of the call and then continue To use the ATQ command set the modem to X3 X4 or X1 If set X2 or lower the modem will return an ERROR message when it encounters the 9 character If set to X5 or X6 the modem hangs up when it detects a voice answer ATDQ Return to Command mode after dialing ATD Semicolon Dial the letters that follow in an alphabetical phone number ATD If you are including another command after the phone number use closing quotation marks before the additional command IMPORTANT With the exception of the above Dial options your modem will ignore any commands issued after the D in the same command string Call a device that can only originate calls It forces the modem to dial out at the answer frequency or Reverse frequencies You can put the R either before or after the number ATDR Display differ
90. dem will load the Hardware Flow Control Template into RAM M emory 5 4 CHAPTER 5 WORKING WITH MEMORY Saving ROM Templates to NVRAM Default Settings All of the settings in each template are given in Appendix C Flow Control Templates For more information about hardware and software flow control See Chapter 12 Flow Control To save one of the three ROM templates to NVRAM and have it serve as the reset default enter arsrnew When the Business M odem is turned on it loads the settings stored in NVRAM By default these settings are that same as the amp F1 template You can save any of the three templates or save modified versions of them in NVRAM for use as power on defaults For your modem to Command Example Display NVRAM settings amp F1 settings ATI5 ATI5 Substitute a template other than amp F1 AT amp F2 amp W AT amp F2 amp W Default Save modified versions of the settings to at lt settings gt sw ATS10240 amp A2 amp W NVRAM See Appendix C Flow Control Templates for a complete listing of the default values e 9 e t e CONTROLLING RESULT CODE DISPLAYS This chapter contains information about a Result Code Display commands wm Additional Result Code subsets Result Code Display Commands The commands listed below control whether result codes are displayed and in what format they are displayed If you want the modem to Command Display result codes ATQO NOT d
91. ea used as temporary storage during input and output operations An example is the modem s command buffer Another is the Transmit Data flow control buffer used for flow control and to store byte call indicate carrier CCITT central office CO central office switch character characters per second cps copies of transmitted frames until they are positively acknowledged by the receiving modem A group of binary digits stored and operated upon as a unit A byte may have a coded value equal to a character in the ASCII code letters numbers or have some other value meaningful to the computer In user documentation the term usually refers to 8 bit units or characters 1 kilobyte K is equal to 1 024 bytes or characters 64K indicates 65 536 bytes or characters A call originating tone defined by ITU T recommendation V 8 A continuous frequency capable of being either modulated or impressed with another information carrying signal Carriers are generated and maintained by modems via the transmission lines of the telephone companies Formerly an international organization that defined standards for telegraphic and telephone equipment It has been incorporated into its parent organization International Telecommunication Union ITU Telecommunication standards are now covered under Telecommunications Standards Sector TSS ITU T replaces CCITT For example the Bell 212A standard for 1200 bps communication in North Amer
92. eceive at higher speeds An ITU T standard for modem communications at 300 bps Modems made in the U S or Canada follow the Bell 103 standard However the modem can be set to answer V 21 calls from overseas A ITU T standard for modem communications at 1200 bps compatible with the Bell 212A standard observed in the U S and Canada An ITU T standard for modem communications at 2400 bps The standard includes an automatic link negotiation fallback to 1200 bps and compatibility with Bell 212A V 22 modems An ITU T standard for modem communications at 1200 bps with a 75 bps back channel Used in the U K An ITU T standard for modem communications Among other things V 25 specifies an answer tone different from the Bell answer tone All 3Com modems can be set with the BO command so that they use the V 25 2100 Hz tone when answering overseas calls Not applicable to the Business M odem An ITU T standard for synchronous communications between the mainframe or host and the modem using the HDLC or character oriented protocol Modulation depends on the serial port rate and setting of the transmitting clock source amp X Not applicable to the Business Modem An ITU T standard for facsimile operations that specifies modulation at 4800 bps with fallback to 2400 bps An ITU T standard for facsimile operations that specifies modulation at 9600 bps with fallback to 7200 bps An ITU T standard for modem communications at 9600 bps and
93. echnical Support for debugging purposes Result Disable 8S 2D mapping Disable 16S 4D mapping Disable 32S 2D mapping Disable 64S 4D mapping Reserved Reserved Reserved Enable phase roll detection 1 8 APPENDIX S REGISTERS Register Default Function 556 Bit mapped register primarily used by 3Com Technical Support for debugging purposes Bit Value Result 0 1 Disable non linear coding 1 2 Disable TX level deviation 2 4 Disable preemphasis 3 8 Disable precoding 4 16 Disable shaping 5 32 Disable V 34 6 64 Disable V 34 7 128 Disable V FC Bit mapped register primarily used by 3Com Technical Support for debugging purposes Bit Value Result 0 1 Disable x2 1 2 Reserved 2 4 Reserved 3 8 Reserved 4 16 Reserved 5 32 Disable V 90 6 64 Reserved 7 128 Reserved Bit mapped register primarily used by 3Com Technical Support for debugging purposes Bit Value Result 0 1 Enable ring type A 1 2 Enable ring type B 2 4 Enable ring type C 3 8 Enable ring type D 4 16 Reserved 5 32 Reserved 6 64 Reserved 7 128 Reserved WARRANTY 3COM CORPORATION LIMITED WARRANTY 3Com OfficeConnect 56K Business Modem 3Com warrants this hardware product to be free from defects in workmanship and materials under normal use and service for the lifetime of the product from the date of purchase from 3Com or its authorized reseller 3Com s sole o
94. ection Stopping a Test for an example of using S18 If you wish to resume data transmission with the remote device add the O command ATO after the ats16 o string to return online If you do this remember that error control is disabled Because error control is negotiated during the connection sequence its status cannot be changed until the Business M odem is back on hook and in Command mode Send at m4 unless you used a reset command ATZ or ATZ Testing Using a Built in Test Pattern ATS16 4 Ending Testing That Uses the Test Pattern Testing the Business Modem using S Resister16 14 11 The test pattern is available at all speeds At 300 bps the Business M odem s serial port rate must be fixed amp B1 and the link rate fixed at 300 bps amp N1 At rates over 9600 bps just set the Business M odem for a fixed serial port rate amp B1 Starting Testing That Uses the Test Pattern To use the test pattern during testing with Command S Register 16 AT amp MOS16 12 The amp T test 1 Send ATS16 4 test pattern command The test pattern is used for testing equipment and the phone line When S16 is set to 4 the Business Modem transmits the test pattern when it connects with a remote device 2 Send ATS16 4 amp T6 Pressing any character key cancels all tests and hangs up the Business M odem If you used Register S16 be sure to reset Register S16 and return to the error control default Send arz or arsm
95. ed See the table in the section amp N and amp U Command Values for connect speed values By setting amp N and amp U values you can limit the range of speeds at which your Business M odem connects If a remote modem does not connect to your Business M odem at a range between the speeds designated by the amp N and amp U commands your Business M odem will not allow it to connect The link speed associated with the amp U argument CANNOT be greater than the link speed associated with amp N argument Use the following table to understand the relationship between amp U and amp N commands If amp U And amp N Then your modem Equals zero Equals zero Connects at the highest possible speed Equals zero Is greater than zero Connects at the amp N speed only Is greater than zero Is greaterthan zero and Connects at the highest possible greater than amp U speed in the range from amp U to amp N 8 6 CHAPTER 8 CONTROLLING DATA RATES amp N and amp U Command Use the following table for a complete list of amp N and amp U link speeds and Values their associated indexes Link Speed Index Highest 0 300 1 1200 2 2400 3 4800 4 7200 5 9600 6 12000 7 14400 8 16800 9 19200 10 21600 11 24000 12 26400 13 28800 14 31200 15 33600 16 28000 17 29333 18 30666 19 32000 20 33333 21 34666 22 36000 23 37333 24 38666 25 40000
96. emote device Sets the duration and spacing in milliseconds of dialed tones q Sets the duration in fiftieths of a second of the guard time ifor the escape code sequence Bit mapped register See Chapter 1 Using the AT Command Set for instructions about how to set bit mapped registers Bit Value Result 0 1 Reset when DTR drops 1 2 Reverse normal Auto Answer operation On incoming RING enter Originate M ode and look for an answer tone 2 4 Disable 250 ms pause before result code display 3 8 On DTR signal autodial the number stored in NVRAM at position 0 4 16 At power on reset autodial number stored in NVRAM at position 0 32 Disable HST 64 Disable M NP Level 3 used for testing Level 2 7 128 Hardware reset works like powering off and then on SI4 Bit mapped register See Chapter 1 Using the AT Command Set for instructions about how to set bit mapped registers Bit Value Result 0 1 Disconnect on escape code 1 2 Send result codes only when originating a call S Registers 1 3 Register Default Function S15 Bit mapped register See Chapter I Using the AT Command Set for instructions about how to set bit mapped registers Bit 0 Value 1 16 32 64 128 Result Disable the Business M odem s extra high frequency equalization if it causes problems on shorter link calls for HST modulation only Disable online fallb
97. ending on local law J 4 APPENDIX J WARRANTY gt GOVERNING LAW This Limited Warranty shall be governed by the laws of the State of California U S A excluding its conflicts of laws principles and excluding the United Nations Convention on Contracts for the International Sale of Goods Important If you send your unit pack it securely and be sure your SRO number is visible on the outside of the package Notices FCC Certification Statement 3Com 3800 Golf Rd Rolling Meadows IL 60008 FCC Registration FCC15 CJE 0263 CJE 0396 FCC68 CJEUSA 73130 FA E CJEUSA 30043 M M E CJEUSA 24161 M 5 E Ringer 0 4B 0 4B Equivalence FCC Notice The user may find the following information prepared by the Federal Communications Commission helpful The CIB Interference Handbook and The CIB Telephone Interference Bulletin These documents are available on the Internet through the FCC Compliance and Interference Bureau Home Page at http www fcc gowcib listed under documents Select CIB Interference Handbook or CIB Telephone Interference Bulletin Any changes or modifications not expressly approved by the party responsible for compliance could void the user s authority to operate this equipment Users should not attempt to make electrical ground connections by themselves but should contact the appropriate inspection authority or electrician as appropriate FCC Notice Radio and Television Interference
98. ent click Details F3 Dial Up Networking an Direct Cable Connection 0 5 VB i Hyper Terminal 0 5 VB df Phone Dialer 0 2 B Ei Space required 0 0 B Space available on disk 36 9 VB Description Enables you to connect to other computers by using a modem y prae omes 6 Click on Dial Up Networking to check the box 7 Click OK OK CHAPTER 1 CONNECTING TO YOUR ISP Insert your Windows 95 98 Setup diskette or CD ROM when you are prompted and Windows 95 98 installs Dial Up Networking Step Two Installing Dial Up TCP IP Support 1 Click Start Settings Control Panel 2 On the Control Panel double click on the Network to display the a uh WN HB N Network window Determine if the TCP IP Dial Up Adapter is installed IF TCP IP gt Dial Up Adapter Do this Is not listed Click Add Protocol Microsoft TCP IP OK Insert your Windows 95 98 Setup diskette or CD ROM when you are prompted and Windows 95 98 installs TCP IP protocol support Is listed Go to Step 3 Step Three Setting Up a Connection to Your ISP Click Start Programs Accessories Dial Up Netw orking Double click Make New Connection Select the correct modem if not already selected Type a name for the connection and click Next Type a phone number for the connection and click Next You should see a message indicating that a new connection was created successfully Click Finish A New Connection icon
99. ent sets of result codes See Chapter 6 Controlling Result Code Displays and Appendix D Result Code M eanings and Sets Dial the last dialed number Use ATDL instead of using A if you wish to send the modem non Dial commands before dialing again ATDL Display the last dialed number ATDL Dial the number stored in nonvolatile random access memory at position n where n 0 9 See Chapter 6 Working with Memory for instructions about saving phone numbers to memory Digits 0 through 9 and are accepted ATDSn Stop dialing or stop repeating Type any key Reissue the last command Don t type AT or press lt ENTER gt A For your modem to Carrier Loss Redial 4 3 Command Dial a number wait 60 seconds for a connection and then hang up Wait two seconds then redial Make a maximum of 10 attempts To stop the repeating press any key during the pause between dial attempts If you press any key while the modem is dialing that dial attempt is canceled but the cycle will continue gt Dial the last dialed number and repeat it just as the gt command does Also can be used to repeat any command A gt Carrier Loss Redial You can set the Business M odem to redial the last dialed number after it loses carrier carrier is the signal maintained between two modems while they are on line This feature is useful for dialed line connections that operate unattended
100. er S16 Only one test can be performed at a given time If you send a test command while the modem is in test mode you ll receive an ERROR message All loopback testing conforms to ITU T Recommendation V 54 14 2 CHAPTER 14 TESTING THE CONNECTION Testing the Business Modem using AT amp Tn To perform digital loopback and remote digital loopback testing use the AT amp Tn command You can type in your own data during testing or use the modem s internal test pattern and error detector See the following sections for more detailed information about each AT amp Tn command For your modem to Command End testing AT amp TO Enter analog loopback AL mode and send a CONNECT AT amp T1 message Data is shown on your screen Enter analog loopback mode and send a CONNECT AT amp T2 message The Business M odem sends a internal test pattern to the transmitter and loops the pattern back to the receiver No data is seen on your screen Start local digital loopback testing AT amp T3 Grant a remote digital loopback test of your Business AT amp T4 Modem Deny a remote digital loopback test of your Business AT amp T5 Modem Start local digital loopback testing AT amp T6 Start remote digital loopback with self test and error AT amp T7 detection Example Sending atets will deny any requests from remote devices for a remote digital loopback test of your Business M odem Disable error control using the amp M 0
101. er system the local echo is invoked through the ATE1 command The command causes the modem to display your typed commands When the modem is online to another system the local echo is invoked through the ATFO command This command causes the modem to display the data it transmits to the remote system M egabyte One million bytes An asynchronous error control protocol developed by M icrocom Inc and now in the public domain The protocol ensures error free transmission through error detection CRC and retransmission of errored frames 3Com modems use MNP Levels 1 4 and Level 5 data compression MNP Levels 1 4 have been incorporated into ITU T Recommendation V 42 Compare HST M ode Indicate M ode Indicate Common Also called fixed or manual originate Used when equipment other than the modem does the dialing In such installations the modem does not respond to AT commands but when taken off hook immediately goes into call originate mode See Microcom Networking Protocol A device that transmits receives computer data through a communications channel such as radio or telephone lines The Business Modem is a telephone channel modem that modulates or transforms digital signals from a computer into the analog form that can be carried successfully on a phone line It also demodulates signals received from the phone line back to digital signals before passing them to the receiving computer User programmable random access memory whose
102. erating at the highest possible speed and constantly ensuring data integrity Continuous varying waveforms such as the voice tones carried over phone lines Contrast with digital signals A state in which the modem transmits at the predefined high frequency of the communications channel and receives at the low frequency The transmit receive frequencies are the re verse of the calling modem which is in originate mode A computer program designed to perform a specific function such as a word processor or a spreadsheet See Automatic Repeat Request American Standard Code for Information Interchange A 7 bit binary code 0 s 1 s used to represent letters numbers and special characters such as and Supported by almost every computer and terminal manufacturer See Adaptive Speed Leveling A transmission technique that splits the communications channel into one high speed channel and one slower channel During a call under asymmetrical modulation the modem with the greatest amount of data to transmit is allocated the high speed channel The modem with less data is allocated the slow or back channel 450 bps The modems asynchronous transmission auto answer auto dial Automatic Repeat Request ARQ baud rate binary digit bit bit bit mapping bit rate bps buffer dynamically reverse the channels during a call if the volume of data transfer changes Data transmission in which the length of time be
103. es for a connection If there is no response within 60 seconds the Business Modem hangs up For more information about adjusting the 60 second wait for connection time using S Register 7 see Appendix A S Registers When a call is disconnected the Business M odem hangs up and returns the NO CARRIER result code If S020 Auto Answer is disabled To determine if Auto Answer is NOT disabled send the command arz4 and be sure that SO 1 255 Hanging up If you want to end a connection with a remote device do the following 1 Enter Online Command Mode by typing 2 Wait 1 second 3 Type ATH Making International calls Handshaking options You can use the ATBn AT amp Gn and ATPn commands for making analog international calls above 1200 bps The ATBn command controls the handshake options If you want your modem Command To answer all V 34 type calls as well as calls from overseas ATBO Default use ITU T formerly CCITT answer sequence NOT to answer V 34 type calls Use Bell answer tone This ATB1 setting selects HST modulation Example Sending ats1 will allow your modem to use Bell answer tone selecting HST modulation 4 6 CHAPTER 4 DIALING ANSWERING AND HANGING UP Guard tone The AT amp Gn command only applies to analog overseas calls at 2400 or 1200 bps To set your modem for Command Required in these countries No guard tone AT amp GO United States and Canada Default 550 Hz guar
104. es that the remote computer does not confuse your XON XOFF characters with those from its attached device This is the recommended setting for ARQ mode When using the AT amp I2 command if the call is not in ARQ mode there is no flow control on the link If you send an XOFF to your modem and it stops passing data it has no way to tell the remote computer and modem to stop sending for a while and the local s buffer may overflow For more reliable control in non ARQ mode see AT amp I5 Enable Hewlett Packard Host mode Applies only to AT amp I3 devices attached to an HP mainframe that uses the ENQ ACK protocol Use in ARQ mode only If you want to use software flow control to transfer non text binary files set serial port and connection rates equal using amp BO and amp NO See Chapter 9 Controlling Data Rates for more information about these commands For your modem to Command Enable Hewlett Packard Terminal mode Applies onlyto AT amp I4 Business M odems attached to terminals in an HP system that uses the ENQ ACK protocol Use in ARQ mode only Enable flow control when the connection is not under error control For this to work the remote device must also have AT amp I5 capability In ARQ mode a Business Modem set to AT amp I5 operates the same as it does when set to amp I2 It acts on your XON XOFF commands but does not pass them to the remote system The error control protocol enables the devices to control the flow
105. ession type V42bis or MNP5 amp Bn Set the serial port rate to variable or fixed amp BO amp B1 amp B2 Variable The serial port rate adapts to match the speed of the connection Fixed The modem always communicates with your computer at the rate at which you have set regardless of the connection rate When answering calls use the fixed rate for ARQ calls and variable rates for non ARQ calls p The serial port rate M UST be equal to or higher than the amp Nn rate Command Function amp Cn Controls how the modem sends a Carrier Detect CD signal to your computer amp CO CD always ON even if the modem is not on line B 6 APPENDIX B ALPHABETIC COMMAND SUMMARY Command Function amp C1 Normal operations The modem sends a CD signal when it connects with another modem and drops the CD when it disconnects amp Dn Control how the modem responds to Data Terminal Ready DTR signals amp D0 DTR is always ON ignored amp D1 If issued before connecting with another device the Business M odem can enter online Command mode during a call by dropping DTR amp D1 functions similarly to the escape code Return online with the On command or hang up with the Hn command amp D2 Normal DTR operations The modem will not accept commands unless your computer sends a DTR signal Dropping DTR ends a call amp D2S13 1 Modem resets with DTR toggle amp Fn Load one of
106. esting This command disables error control fixes the connection rate at 2400 bps and makes the Business M odem return to command mode when you type the escape code 2 Establish a connection with the remote device 3 If you haven t already done so arrange with the remote user to cooperate with the test If necessary set the remote device to acknowledge the remote digital loopback request For example older 3Com modems need to be set to S16 8 Send AT amp T7 to the modem The modem enters remote digital loopback mode and the MR status light flashes The Business M odem sends its built in test pattern to the remote device which loops it back to your Business Modem You will not see the data on your screen Send the escape code and then artero to end the test You can also end the test by sending aru arz or atz Be careful though because ATZ and ATZ reset the Business M odem in addition to ending the test If you issue an invalid command the Business M odem sends an ERROR message If you set Register S18 the Business Modem automatically ends the test when the test timeout is reached See the example in the previous section Stopping a Test for an example of using S18 When the test ends the Business M odem returns a three digit code followed by OK A code of 000 indicates no errors were found a code of 255 indicates 255 or more errors Data errors indicate a problem with the remote device or with the phone
107. et to 516 8 Send AT amp T6 to the modem The modem enters remote digital loopback mode and the MR status light flashes Type a short message It will be looped back to your modem by the remote device and to your screen for verification The remote user will not see your data Send the escape code and then artero to end the test Alternatively you can end the test by sending aru arz Or atz Be careful because ATZ and ATZ reset the Business M odem in addition to ending the test If you issue an invalid command the Business Modem sends an ERROR message If you set Register S18 the Business M odem automatically ends the test when the test timeout is reached See the example in the previous section Stopping a Test for an example of using S18 Data errors indicate a problem with the remote device or with the phone link 7 Send atema unless you used a reset command ATZ or ATZ 14 8 CHAPTER 14 TESTING THE CONNECTION Testing Using a Built in Test Pattern AT amp T7 This test option causes the modem to perform a remote digital loopback test by sending a built in test pattern An internal error detector counts any errors and when the test is ended sends the number of errors or 000 no errors to the screen Follow the steps below However you don t need to type anything during this test The modem sends only its final error count to your screen Send AT amp MO amp N3S14 0 0 to prepare the Business M odem for t
108. for use with a SLIP connection Double click Dial Up Networking Click New Select the Server tab and select SLIP in the Dial up server type box Click TCP IP settings Enter the IP address provided by your ISP Enter the primary DNS and secondary DNS server IP addresses in the appropriate name server address boxes If your ISP requests that you use a specific frame size select the desired frame size in the Frame Size box 1 12 CHAPTER 1 CONNECTING TO YOUR ISP Troubleshooting RAS RAS is significantly easier to troubleshoot then Win95 Dial Up Networking there are a finite number of problems that one runs into on a daily basis and the majority of these are caused by misconfiguration M ost connection problems can be solved by following these steps a In the Basic tab Make sure that the phone book entry settings are correct a Make sure Use Telephony Dialing Properties is unchecked m Make sure to that Use another port if busy is not checked wm Inthe phone book settings under security it should be set to Accept any authentication including clear text a Make sure only the necessary network protocols are selected a In the Connect to window after you click Dial there should be no domain set This is only for logging into NT domains m Make sure that the TCP IP settings are correct This is a general setup for your Business M odem using Windows NT If you are having problems connecting to you ISP configuring Dial U
109. formation about configuring the EIA 2321 signalling between your computer and modem m Data Terminal Ready a Data Set Ready a Carrier Detect Data Terminal Ready Your computer sends a Data Terminal Ready DTR signal to the Business M odem when it is ready to send and receive data The amp Dn command tells the modem how to respond to the DTR signal For your modem to Command Ignore the state of DTR and act as if DTR is always present Use AT amp DO this command with equipment that cannot provide DTR If issued before connecting with another device enter online AT amp D1 Command M ode during a call by dropping DTR Most communications software packages have a method for toggling DTR Refer to your software s manual for details Respond normally to the DTR signal AT amp D2 The Business M odem will not accept commands until your computer sends a DTR signal The call will end when the DTR signal is dropped To change the DTR recognition time set S Register 25 See Appendix A S Registers for more information Business M odem hangs up and resets upon loss of DTR signal AT amp D3 Example Sending aran before connecting with another device dropping DTR will enter Command Mode 1 The EIA 232 Standard was formerly known as RS 232 RS stands for Recommended Standard 7 2 CHAPTER 7 CONTROLLING EIA 232 SIGNALING Data Set Ready A Under normal conditions the Business Modem sends a Data Set Ready
110. g Loopback AL mode Your modem will send a CONNECT message Data is shown on your screen amp T2 Enter AL mode and send a CONNECT message The Business M odem sends an internal test pattern to the transmitter and loops the pattern back to the receiver No data is seen on your Screen amp T3 Start local digital loopback testing amp T4 Grant a remote digital loopback test of your modem amp T5 Deny a remote digital loopback test of your modem amp T6 Start remote digital loopback testing amp T7 Start remote digital loopback with self test and error detection amp Wn Write the current settings to NVRAM amp Yn Break handling This command lets you send a break to stop data transfer without disconnecting Command Percent 96 Command Set B 11 Function amp Y0 Destructive don t send break amp Y1 Destructive expedited amp Y2 Nondestructive expedited amp Y3 Nondestructive unexpedited the modem sends a break in sequence with data received from your computer or terminal If the call is under MNP5 data compression destructive breaks cause both modems to reset their data compression tables When transmission resumes the modems build new tables and the result is lower than normal throughput Command Function amp Zn s Store up to 10 numbers in NVRAM where n is the position 0 9 in NVRAM and sis the phone number string The number string may be up to 36 characters long including any Dial
111. hat your dealer will be able to give you the assistance you need This is much more efficient and time saving than returning the product to 3Com Corporation 3 If your dealer can t help you refer to the Getting Started Guide provided in this package This guide lists several important 3Com numbers 4 If you must return your Business M odem to us the Service Representative you talk with will give you a Service Repair Order SRO number Products without an SRO number will not be accepted Problems that Occur After Connecting 15 7 5 If you do return the Business Modem to us please follow these procedures a Ship the unit postage pre paid in its original container If the original container is not available pack the unit carefully in a strong box of corrugated cardboard with plenty of packing material b Be sure to include your SRO number inside the package along with your name and address Put your return address and your SRO number on the shipping label as well c Ship the package to the following address 3Com Corporation SRO attn Dock 15 PCD 1800 West Central Mount Prospect IL 60056 3Com will not accept packages sent COD so be sure to send the modem postage paid 3Com will repair your Business M odem and return it to you via United Parcel Service 15 8 CHAPTER 15 TROUBLESHOOTING UPGRADING YOUR MODEM e o e t e This chapter contains information about m Checking your m
112. he Business M odem Dial Security will be disabled Decide which Dial Security option to use You can choose from the two types of Dial Security Autopass and Password Prompting Autopass Prompting Passw ord Prompting Autopass is the default form of password protection Autopass automates the process of logging in to the host modem but it requires the guest and host devices to be Business Modems When a guest device attempts an Autopass connection the guest includes its password in its V 42 error control request The host modem checks all the enabled passwords in its security accounts for a match Password Prompting allows connections with any guest device as long as the guest user knows the correct password When the host has Password Prompting enabled it asks guest users for a password The host modem checks the received password against each of its active Security accounts The table below is a comparison between Autopass and Password prompting When using Autopass Prompting When using Password Prompting Both the host and guest devices are made by 3Com and have Dial Security enabled Guest devices don t have to support 3Com Dial Security The connection between the Business Modems or modems is under V 42 error control See Appendix B Alphabetic Command Summary for information about using AT amp M4 or AT amp M5 V 42 error control connections aren t required If the guest includes an invalid p
113. he Business Modem To avoid redundancy use the above protocols only for non ARQ connections and only at speeds of 2400 bps and below Getting Maximum Throughput 12 11 Overhead is minimal with ZMODEM resulting in throughput that is almost equal to that obtained with no file transfer protocol ZMODEM should also be used for non ARQ connections Leave the Business Modem at its amp M 4 and amp K1 settings for both error control and data compression YMODEM G is another good choice but never use it unless both the local and remote devices are using error control if YM ODEM G detects an error it aborts the transfer Do not use either protocol with software flow control XON XOFF signaling 13 E247 e t e DISPLAYING QUERYING AND HELP SCREENS This chapter contains information about a Querying wm Displaying help To view screen captures of the help screens in the following chapter see Appendix B Alphabetic Command Summary Overview The Business M odem can display information such as the current settings product code and call duration Common Inquiry Commands For your modem to display Command Current settings ATIA NVRAM settings ATI5 Link diagnostics summary ATI6 Querying Here is a complete list of ATIn commands For your modem to Command Display a four digit product code ATIO Perform a checksum of the modem s read only ATI1 memory ROM and display the results This fun
114. ial settings Displaying S Register settings gt Setting an S Register A Using S Registers 2 3 You can display S Registers in a variety of ways See the table below for more information To display Command Contents of ONE S Register ATSr where r is the register s number S Register settings in the NVRAM templates ATI5 S Register settings in RAM the current configuration ATIA Example Sending atso displays the contents or setting for S Register 0 When using the commands ATI4 and ATI5 S Register settings appear as a table seven columns wide each entry of the form Smm nnn where mm is a register number between 0 and 70 and nnn is a decimal value between 0 and 255 You can configure each S Register setting manually CAUTION If you do not write an S Register setting with amp w the setting will be retained only until the next reset or power off To change Command Settings for a register in the current configuration ATSr n Example Sending arso 2 changes the setting for S Register 0 to 2 This setting will cause the Business M odem to answer in Auto Answer Mode on the second ring In the command ATSr n r is the register s number and n is a decimal value from 0 255 unless otherwise indicated that specifies the setting 2 4 CHAPTER 2 USING THE AT COMMAND SET Getting a list of S Registers gt To display Command A list of S Registers ATS In order to issue this command
115. ica was referred to as CCITT V 22 It is now referred to as ITU T V 22 The facility to which devices such as telephones fax machines and modems within a specific geographic area of a public telephone network are connected A device located at the telephone company s central office to which devices such as telephones fax machines and modems are connected A representation coded in binary digits of a letter number or other symbol A data transfer rate generally estimated from the bit rate and the character length For example at 2400 bps 8 bit characters with start and stop bits for a total of ten bits per character will be transmitted at a rate of approximately 240 characters per second cps Some protocols such as HST and MNP employ advanced techniques such as longer transmission frames and data compression to increase cps Class 1 EIA 578 Class 2 0 EIA 592 co COM port cps CPU CRC cyclic redundancy check CRC data communications data compression data compression table data communication equipment DCE An American standard used between facsimile application programs and facsimile modems for sending and receiving Class 1 faxes An American standard used between facsimile application programs and facsimile modems for sending and receiving Class 2 0 faxes See central office See serial port EIA 232 See characters per second Central processing unit See cyclic redundancy check
116. ical Support may ask you to disable V 32bis for testing purposes 1 6 APPENDIX S REGISTERS Register Default Function Bit Value Result 1 2 Disable the Business M odem s enhanced proprietary V 32bis modulation Used for troubleshooting 2 4 Disable the faster retrains that occur during proprietary V 32terbo modulation Used for troubleshooting 3 8 Enable V 23 Required for some British connections 6 64 Disable the remote access busy message 7 128 Disable V 32terbo 538 Sets the duration in seconds before a forced hang up and clearing of the Transmit buffer when DTR drops during an ARQ call This is provided to allow time for a remote device to acknowledge receipt of all transmitted data Default 0 The Business Modem immediately hangs up when DTR drops If the Business Modem receives the ATH command it ignores S38 and immediately hangs up SAT Sets the number of allowable remote access login attempts thus enabling or disabling remote access The default setting of zero allows no remote login attempts thus disabling remote access A value of 1 or greater enables remote access If the number of unsuccessful login attempts exceeds the limit set by this register the Business M odem returns online and any further login attempts during the remainder of that connection are refused 542 Stores the ASCII decimal code for the remote access escape character The default character is a tilde
117. in text in one of two ways m Referred to by their labels such as the Return key or the Escape key a Written with brackets such as Return or Esc If you must press two or more keys simultaneously the key names are linked with a plus sign 4 Example Press Ctrl Alt Del Menu commands and buttons M enu commands or button names appear in italics Example From the Help menu select Contents Table 2 Text Conventions continued Convention Description Words in italicized Italics emphasize a point or denote new terms at the place type where they are defined in the text Words in bold face Bold text denotes key features type Related The 3Com OfficeConnect 56K Business M odem Installation Guide should Documentation be used for the installation of the Business Modem Year 2000 For information on Year 2000 compliance and 3Com products visit the Compliance 3Com Year 2000 web page http www 3com com products yr2000 htm eee e t CONNECTING TO YOUR ISP This chapter contains information about configuring your modem for various operating systems a Windows 95 98 m Windows NT 4 0 and Later m Macintosh m Other Operating Systems Windows 95 98 gt What You Need Configuring Your modem with Plug and Play The first time you start Windows 95 98 after you ve installed the modem Windows 95 98 will auto detect your modem Since Windows 95 98 supports Plug and
118. install the communications software package that is included on the Connections CD ROM Because Windows Terminal only supports speeds up to 19200 bps it is recommended that you use a third party communications software package Because there is no communications software built in to MS DOS you must install and run a third party communications software package to operate your modem RapidComm which is included on the Connections CD ROM contains MS DOS and Windows 3 1 versions of RapidComm You must choose the COM port to which your modem is attached in whatever communications software package you are using For instructions about how to set up your UNIX Linux or AIX communications software package see the software s installation procedure 1 18 CHAPTER 1 CONNECTING TO YOUR ISP eee e t e USING THE AT COMMAND SET This chapter includes information about m Basic AT commands m Using S Registers a Understanding bit mapped S Registers Overview General rules for using AT commands gt You can use AT commands to change your modem settings at any time To send AT commands to your modem you need to put your communications software in Terminal M ode In terminal mode what you type is sent directly to the modem You must follow some general guidelines to send AT commands to your modem m Type AT before each command and press ENTER after each command The exceptions are A A gt
119. internet service providers Domain Name Server Address DNS numbers in the Name server addr box A WN HB 5 Leave the other fields empty Configure Using PPP Server T Select Hosts File Implicit Search Path Starting domain name IF Address will be supplied by server gt O Subnet mask will be supplied by server gt Ending domain name i will be supplied by server a Additional Search domains Router address Name server addr 149 112 96 999 DCm 1 16 CHAPTER 1 CONNECTING TO YOUR ISP Setting up your ISP information 1 Goto Apple Menu Control Panels PPP 2 In the PPP window select Registered User 3 Type in your Internet Service providers login name and your password in the name and password boxes 4 Put the phone number that you dial to connect to your internet provider in the number box Connect via Modem Connection e amp Registered User Q Guest Name lusr Password Save password Number 2221107 connect You ve successfully configured Open Transport PPP Other Operating Systems If You Are Using Windows 3 x If You Are Using MS DOS If You Are Using UNIX Linux or AIX This sections explains how to configure your modem for a Windows 3 x a MS DOS m UNIX Linux or AIX Windows 3 x comes with a built in communications software package Windows Terminal You can use Windows Terminal to test your modem or you can
120. is transmitting to another modem F0 Online echo ON Sometimes called half duplex F1 Online echo OFF Sometimes called full duplex Hn Go on or off hook HO Go on hook hang up H1 Go off hook pick up In Query the modem I3 Displays the banner product name 14 Display current modem settings 15 Display settings stored in NVRAM l6 Display statistics for the last call 17 Display product configuration 110 Display dial security account status information 111 Display connection report contains symbol rates 115 Display caller ID information B 4 APPENDIX B ALPHABETIC COMMAND SUMMARY Command Function Kn Control the modem clock ATI6 displays the time KO If online display current call duration If offline display last call s duration K1 Display the actual time Set the clock using ATI3 HH M M SS K1 Mn Control when the speaker sounds MO The speaker is always off M1 The speaker is on until the call is negotiated M2 The speaker is always on M3 The speaker turns on after the last digit is dialed and stays on until the call is negotiated On Return online Use with the escape code to toggle between command and online modes 00 Return online normal O1 Return online and retrain Use O1 if there were errors in a non ARQ data transfer Qn Enable or disable the display of result codes Qo Display result codes Q1 Suppress result codes quiet Q2 Suppress resul
121. isabled If you need a reference when setting these command you can use the ATI10 command See Appendix B Alphabetic Command Summary for more information about the ATI10 command 7 Send artz or artz to activate the Dial Security settings Maintaining Security Accounts gt Remote Configuration Once the administrative password is set and Dial Security is enabled the administrator is the only one who can access account information You can use the AT S and AT E commands to change and modify account information For your modem to Command Access accounts by disabling local security AT S administrative password View account information once accesshasbeen ATI10 granted Remote users may only use this command during remote access sessions if local access security is disabled Erase local access passw ord AT SE 1 Erase Autopass password ATSE 2 Erase passwords in accounts 0 9 AT E 3 Erase phone numbers in accounts 0 9 AT E 4 Disable Account Dialback and New Number ATSE 5 fields in accounts 0 9 Edit or overwrite an individual account or an ATSAn individual account field wheren is the account number see the figure in previous section Setting Up Dial Security for more information Reset amp F settings and disbale password Press the RESET button on the protection back of the modem when offline same as ATSFS53 0 Example Sending arsE 3 erases passwords for accounts 0 9
122. isplay result codes ATQ1 NOT display result codes while in Answer mode See Chapter ATQ2 4 Modes of Operation for a description of modes Display result codes in numeric form ATVO Display result codes in verbal form ATV1 Display result codes when originating answering and ATS14 1 0 retaining a call Display result codes ONLY when originating a call ATS14 1 1 Display sets of result codes See Appendix D Result Code Sets ATXn and M eanings Default ATX7 6 2 CHAPTER 6 CONTROLLING RESULT CODE DISPLAYS Additional Result Code Subsets ARQ Automatic Repeat Request is used in this manual to denote calls that use error control For your modem to Command Display only connection rate AT amp AO Display connection rate and ARQ result codes AT amp A1 Display connection rate ARQ result code and protocol AT amp A2 information V32 VFC V34 or x2 v 90 If your software cannot handle the added protocol information select amp A1 or amp A0 Display connection rate ARQ result code protocol error AT amp A3 Default control LAPM M NP or NONE and data compression type V42BIS M NP5 indicators The numeric identifiers for amp A3 result codes are the same as those used for amp A2 If you request numeric display V0 and amp A3 you won t be able to distinguish amp A2 from amp A3 codes 20 they e t e CONTROLLING EIA 232 SIGNALING This chapter contains in
123. itish connections Register Default Function 4 16 Change MR to DSR 6 64 Disable the remote access busy message 7 128 Disable V 32terbo 38 0 Sets the duration in seconds before a forced hang up and clearing of the Transmit buffer when DTR drops during an ARQ call This is provided to allow time for a remote device to acknowledge receipt of all transmitted data Default 0 The Business Modem immediately hangs up when DTR drops If the Business Modem receives the ATH command it ignores S38 and immediately hangs up S41 0 Sets the number of allowable remote access login attempts thus enabling or disabling remote access The default setting of zero allows no remote login attempts disabling remote access A value of 1 or greater enables remote access If the number of unsuccessful login attempts exceeds the limit set by this register the Business Modem returns online and any further login attempts during the remainder of that connection are refused S42 126 Stores the ASCII decimal code for the remote access escape character The default character is a tilde S43 200 Sets the duration in fiftieths of a second of the guard time for the remote access sequence S44 15 Sets the duration in seconds of the interval between losing carrier and reestablishing a connection 51 0 Bit mapped register See the beginning of this appendix for information about setting bit mapped registers Bit Value Result 0 1
124. itter and loops the pattern back to the receiver You will not see any data on your screen Send the escape code and then atero to end the test Alternatively you can end the test by sending ATH or ATZ Be careful because ATZ resets the modem in addition to ending the test In any case the Business M odem hangs up and returns a three digit code followed by OK The code Indicates 000 No errors were found 255 255 or more errors An ERROR message indicates that you issued an invalid command 4 Send arem4 unless you used a reset command ATZ or ATZ Testing the Business Modem using AT amp Tn 14 5 Digital Loopback This test can help you locate a problem with a remote device or with the telephone line The figure below shows the data flow during Digital Loopback DL testing Testing AT amp T3 q WwW N U R Telco Telco p ensite xe TX To DTE _ PEA Local Transmitter ED To DTE Receiver No Receiver LA RX Remote Send the command aT amp M0 amp N3s14 0 0 to the modem to prepare for testing This command disables error control fixes the connection rate at 2400 bps and makes the Business M odem return to command mode when you type Establish a connection with the remote device Send the Business M odem the escape code to bring it back to Command mode Send
125. king Data Compression and Error Control for more information about ARQ correct rate is maintained The serial port rate M UST be equal to or higher than the Connection rate amp Nn Connection Rates You can set the Business M odem to a fixed or variable connection rate for data calls Set a variable rate to have the Business M odem negotiate with the remote device for the highest possible connection rate Set a fixed rate to connect only at a specified rate You might use a fixed rate to filter calls for security or other reasons To allow your modem to Set connection rate as Command Negotiate for the highest possible rate Variable AT amp NO Connect only if the remote device is Fixed AT amp N1 AT amp N16 operating at the rate you specify See below To connect at this To connect at this rate Command rate Command 300 bps AT amp N1 16 8 Kbps AT amp N9 1200 bps AT amp N2 19 2 Kbps AT amp N10 2400 bps AT amp N3 21 6 Kbps AT amp N11 4800 bps AT amp N4 24 0 Kbps AT amp N12 7200 bps AT amp N5 26 4 Kbps AT amp N13 9600 bps AT amp N6 28 8 Kbps AT amp N14 12 0 Kbps AT amp N7 31 2 Kbps AT amp N15 14 4 Kbps AT amp N8 33 6 Kbps AT amp N16 Example Sending atens will only allow connections with remote devices that are operating at 14 4 Kbps 8 4 CHAPTER 8 CONTROLLING DATA RATES Controlling Link Speeds with amp N and amp U Controlling Link Speeds p Limiting the Highest Possible Connect
126. l parameters P Dial using pulses Accepted but ignored T Dial using tones Accepted but ignored Comma Pause for 2 seconds or the time in S Register 8 Accepted but ignored Semicolon Remain in Command mode after dialing i Dial the letters that follow W Wait for a second dial tone before continuing dialing with X3 or higher Accepted but ignored Wait for an answer with X3 X4 or X7 Accepted but ignored if Pause for 125 milliseconds Accepted but ignored R Reverse frequencies Use this command when calling an originate only modem It forces the modem to dial out at the answer frequency gt Basic Command Set B 3 Flash the switchhook off hook 0 5 seconds on hook 0 5 seconds then off hook Use when other modems share the line L Display the last dialed number L Dial the last dialed number Sn Dial the number stored in memory at position n where n 0 9 Store the number in memory using the amp Z command Display help for the dial commands En Command mode echo Enables or disables the display of your typed commands E0 Command mode echo OFF Your typing will not appear on the screen El Command mode echo ON Your typing will appear on the screen If double characters appear on the screen both the modem s local echo and your software s local echo are on Command Function Fn Online local echo If ON a modem displays on your screen the data that it
127. les which lessens throughput The additional data is stripped when the file is decompressed by the remote modem When transferring such files it s best to set the modem to amp K3 See the information in data compression This allows V 42bis compression to work dynamically with the compressed data but disables M NP5 Getting Maximum Throughput Maximum throughput results when The following guidelines should help you to make the most of the Business M odem s advanced performance features In many instances experimentation and experience will indicate what works best for your applications a The communications software allows fixing the serial port rate higher than the connection rate by setting the software to 115200 57600 or 38400 bps and setting the Business Modem to amp B1 If the software automatically switches serial port rates to follow the connection rate the Business M odem s serial port rate must be also set to follow the connection rate for each call amp BO and throughput will be limited 12 10 CHAPTER 12 HANDSHAKING ERROR CONTROL DATA COMPRESSION AND THROUGHPUT gt Installations with specialized software may want to enable a fixed serial port rate for ARQ calls and a variable serial port rate for non ARQ calls See the amp B2 command in Appendix B Alphabetic Command Summary a The call is under data compression a The data is made up of text files rather than binary files such as EXE or
128. ly contains in a margin at the top or bottom of each transmitted page or on the first page of the transmission the date and time it is sent and an identification of the business other entity or individual sending the message and the telephone number of the sending machine or of such business other entity or individual Telephone facsimile machines manufactured on and after December 20 1992 must clearly mark such identifying information on each transmitted page Notes If you want to know more about the supported Class 1 fax commands refer to the standard for the Service Class 1 fax protocol ANSI EIA TIA 578 1990 EIA 578 Asynchronous Facsimile DCE Control Standard November 1990 Approved October 22 1990 For more information on Class 2 0 refer to the standard for the Service Class 2 0 fax protocol ANSI EIA TIA 592 1993 EIA 592 Asynchronous Facsimile DCE Control Standard May 1993 You can obtain copies of these standards by contacting Global Engineering Documents at 1 800 854 7179 VIEWING LEDS This appendix explains how to view the twelve LEDs on the front of your Business M odem This LED Status Means your Business Modem Alert On Has detected a firmware dowload error Flashing Firmware update in progress Off Normal operation Power On Is switched on Off is switched off Fax On Is currently configured for fax operation Off is not currently configured for fax operation ARQ On I
129. m shall not be responsible for any software firmware information or memory data of Customer contained in stored on or integrated with any products returned to 3Com for repair whether under warranty or not WARRANTIES EXCLUSIVE IF A 3COM PRODUCT DOES NOT OPERATE AS WARRANTED ABOVE CUSTOM ER S SOLE REM EDY FOR BREACH OF THAT WARRANTY SHALL BE REPAIR REPLACEM ENT OR REFUND OF THE PURCHASE PRICE PAID AT 3COM S OPTION TO THE FULL EXTENT ALLOWED BY LAW THE FOREGOING WARRANTIES AND REM EDIES ARE EXCLUSIVE AND ARE IN LIEU OF ALL OTHER WARRANTIES TERM S OR CONDITIONS EXPRESS OR IM PLIED EITHER IN FACT OR BY OPERATION 3COM CORPORATION LIMITED WARRANTY J 3 OF LAW STATUTORY OR OTHERWISE INCLUDING WARRANTIES TERM S OR CONDITIONS OF M ERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE SATISFACTORY QUALITY CORRESPONDENCE WITH DESCRIPTION AND NON INFRINGEM ENT ALL OF WHICH ARE EXPRESSLY DISCLAIM ED 3COM NEITHER ASSUM ES NOR AUTHORIZES ANY OTHER PERSON TO ASSUME FOR IT ANY OTHER LIABILITY IN CONNECTION WITH THE SALE INSTALLATION MAINTENANCE OR USE OF ITS PRODUCTS 3COM SHALL NOT BE LIABLE UNDER THIS WARRANTY IF ITS TESTING AND EXAM INATION DISCLOSE THAT THE ALLEGED DEFECT OR M ALFUNCTION IN THE PRODUCT DOES NOT EXIST OR WAS CAUSED BY CUSTOMER S OR ANY THIRD PERSON S MISUSE NEGLECT IM PROPER INSTALLATION OR TESTING UNAUTHORIZED ATTEM PTS TO OPEN REPAIR OR M ODIFY THE PRODUCT OR ANY OTHER CAUSE BEYOND THE RANGE OF THE INTENDED
130. means there is communication with the device on the other end of the connection Under normal conditions the Business Modem sends a Carrier Detect CD signal in response to establishing a connection with another modem You can use the AT amp Cn command to control how the Business M odem sends the CD signal For your modem to Command Have CD always ON AT amp CO Send CD normally the Business Modem sends a CD signal AT amp C1 when it connects with another device and drops the CD signal when it disconnects 7 4 CHAPTER 7 CONTROLLING EIA 232 SIGNALING e eee CONTROLLING DATA RATES This chapter contains information about m Serial port rates Connection rates Controlling Link Speeds with amp N and amp U m Setting DTE Rate to 230 Kbps Overview You can set the Business M odem to use fixed or variable serial port rates and fixed or variable connection rates Serial port rates pertain to data transferred between your computer and the Business M odem Connection rates pertain to data transferred between the Business M odem and the device at the other end of a connection Serial Port Rates You set a fixed serial port rate to get the highest possible throughput and the best performance Set a variable rate to allow the Business M odem to match the connection rate Your software must support fixed or variable serial port rates 8 2 CHAPTER 8 CONTROLLING DATA RATES gt gt Yo
131. mitted character The bit s value is 0 or 1 to make the total number of 1 s in the character even or odd depending on which type of parity is used A variation of the standard ISA bus that attempts to automate the troublesome process of resolving the IRQ and COM port conflicts that can arise when new devices are installed in ISA bus computers A protocol used to send data over serial lines PPP provides error checking link control and authentication and can be used to carry IP IPX and other protocols PPP is superseding SLIP as the leading dial in protocol A system of rules and procedures governing communications between two or more devices Protocols vary but communicating devices must follow the same protocol in order to exchange data The format of the data readiness to receive or send error detection and error correction are some of the operations that may be defined in protocols Another way of saying setting up telephone lines See Random Access M emory Random Access M emory M emory that is available for use when the modem is turned on but that clears of all information when the power is turned off The modem s RAM holds the current operational settings a flow control buffer and a command buffer 10 GLOSSARY Read Only Memory ROM remote access remote digital loopback remote echo result code RJ11 ROM Serial Line Internet Protocol SLIP serial port serial transmission software flow
132. nable Caller ID with formatted output AT CID 1 Enable Caller ID with unformatted output AT CID 2 References Caller ID Action Command Enable Caller ID with formatted output and name AT CID 3 suppressed Enable Caller ID but do not transmit the AT CID 4 information to your computer retain it in the Business Modem s memory Display the current caller ID setting AT CID Display the Caller ID settings that are available AT CID For more information about Calling Number Delivery CND refer to Bellcore documents TR TSY 000030 and TR TSY 000031 To obtain Bellcore documents contact Bellcore Customer Service 8 Corporate Place Room 3A184 Piscataway NJ 08854 4196 800 521 2673 Distinctive Ring Support Distinctive ring is a service provided by local telephone companies that permits the assignment of multiple phone numbers to one line Each phone number is associated with a different ring pattern and devices that recognize distinctive ring like the Business M odem can be set to answer only on certain incoming ring patterns For example a fax machine answering machine telephone and modem could all share the same line Each device would have its own phone number and respond only to calls intended for that number Commands There are four ring patterns in common use Ring Description A 1 2 to 2 0 seconds on 4 0 seconds off B 0 8 second on 0 4 second off 0 8 second on 4 0 seconds off
133. nction Bit Value Result B 8 Disable 2100 Hz answer tone to allow two V 42 devices to connect more quickly 16 See next page 32 See next page 128 Unusual software incompatibility Some software may not accept some result codes This setting disables the codes and displays the 9600 code instead The call s actual rate can be viewed on the ATI6 screen Error control handshaking options Select the total value of bits 4 and 5 0 0 Complete handshaking sequence V 42 Detection LAPM error control MNP 16 0 Disable M NP 0 32 Disable V 42 Detection and LAPM 16 32 Disable Detection phase if you know that the remote modem does LAPM but not the Detection phase 528 ets the duration in tenths of a second of the extra 3000 600 Hz answer tones sent during V 32 hand shaking This gives V 32 modems additional time to connect in V 32 mode before timing out If there is difficulty answering older manually operated V 32 modems for example modems that require a button to be pushed in order to dial try lengthening the duration of the extra tones Setting S28 ko zero eliminates the extra tones resulting in a faster connect time if for example the Business Modem is set to use V 21 modulation 300 bps or V 23 modulation 1200 bps 534 Bit mapped register See Chapter 1 Using the AT Command Set for instructions about how to set bit mapped registers Bit Value Result 0 1 Disable V 32bis Used for troubleshooting 3Com Techn
134. nd the file to your modem using the XM ODEM Checksum or XM ODEM CRC protocol Since this is a test the modem s existing software is not erased 4 After you ve completed the test transfer successfully use your communications software to send the XMD file using the XM ODEM Checksum or XM ODEM CRC protocol See below at x SDL Xmodem file transfer Y es N o T est y Begin Xmodem file transfer now CC SDL Xmodem file transfer completed Calculating CRC OK Resetting modem OK Once you see the OK response to the Calculating CRC and Resetting modem messages your software upgrade is complete If Your Modem Doesn t Respond If your modem doesn t respond after the flash process its memory may be corrupted Follow these steps to force the new software to the modem Power your modem off The power switch is in the rear right corner of the back panel While holding in the RESET button between the RS 232 and USB jacks turn the modem back on Start your communications software package Set your port speed to 57 600 bps type ar and press Enter If the Business M odem reports Corrupt Firmware issue the at x command and repeat the flash process found on the previous page eete e S REGISTERS Understanding Bit Mapped S Registers A bit mapped S Register uses one number to describe a collection of settings Bit mapping allows us to pack a lot of information in a small space Bit mapped regis
135. nection In order to negotiate V FC V 8 hasto be disabled V FC is not part of the ITUV 8 training sequence If the remote device is not V FC capable a connection is made using the highest compatible modulation scheme V 32 terbo V 32 bis and so on down to as low as Bell 103 or 300 bps HST USR V 32terbo to USR V 32terbo If the remote device has V FC capability the Business M odem uses a line probing technique to determine the highest speed possible under current line conditions then completes the connection If the remote analog device does not have V FC capability the Business M odem listens to the device s answer tones to identify what standard rate the remote analog device is operating at and adjusts to that rate When a Business M odem answers a call it sends out a series of answer tone signals until both devices negotiate the best connection rate We recommend that Business M odems retain the default BO and amp NO settings This allows them to make analog connections with V protocol and HST modems in both Originate and Answer modes at a variety of speeds When originating an analog call the Business M odem set to B1 sends out a Bell answer tone which is the prevalent standard in the U S and Canada for connections at 2400 bps and lower At higher speeds the Business M odem also recognizes the ITU answer tones necessary for connecting with V protocol modems and adjusts to the answering device However when
136. odem s software version m Getting new operating software m Sending new software to the modem m f your modem doesn t respond Overview 3Com periodically releases updates and enhancements to the modem s operating software which are made publicly available from our Web site BBS and ftp site Checking Your Issuing the arz7 command produces the following information Business M odem s Software Version ati 3Com OfficeConnect 56K Business Modem Configuration Profile Product type US Canada External Options HST V32bis Terbo V FC V34 Fax Options Class 1 Class 2 0 Clock Freq 20 16Mhz Eprom 256k Ram 32k Supervisor date 04 02 96 DSP date 09 28 95 Supervisor rev 6 4 5 DSP rev 1 3 0 OK 16 2 CHAPTER 16 UPGRADING YOUR MODEM Check the Supervisor and Digital Signal Processor DSP dates found in the last two lines of the screen display These dates will determine which version of the software your modem is using The best way to find out the current shipping version of the modem s software is to visit the 3Com U S Robotics Web site at http ww w usr com home online Getting New Operating Software To get the newest version of the Business M odem s operating software a Go to the 3Com U S Robotics Web site at http www usr com home online Select Upgrades Updates You will then have a choice of having the site help you determine your product code or entering the product code directly Once you have product co
137. of data on the phone link In non ARQ mode a Business Modem set to AT amp I5 operates as though flow control were disabled AT amp IO it does not look for your typed XON XOFF commands However it does look for XON XOFF characters coming in over the phone link When the remote device sends XON XOFF commands the Business M odem either resumes or stops transmitting data over the link and drops the characters from the data stream If both devices are set to AT amp I5 operators at each end can AT amp I5 signal the remote device to stop sending Thus controlling the data flow on the phone link and preventing their own device s buffer from overflowing At the computer device interfaces the devices independently control the flow of data through their Transmit Data AT amp H settings Example Sending ar zr2 will remove XON XOFF commands from the data stream instead of sending them to the remote computer This will force the Business M odem to act of the XON XOFF commands Transmit Data Flow Control 11 5 Transmit Data Flow This type of flow control is for data transmitted to the Business Modem Control by its attached computer For your modem to Command Disable transmit data flow control AT amp HO Enable Hardware flow control AT amp H1 Requires that your computer and software support Clear to Send CTS at the EIA 232 interface Enable Software flow control AT amp H2 Requires that your software support XON
138. om were not fully compatible with the MNP protocol If you have difficulty making a successful 2400 bps MNP connection with a remote MNP modem it may be because of this incompatibility Set S15 to 64 and try again to make the connection 7 128 Custom applications only The default 1 5K byte non ARQ buffer allows data transfer with X and Y modem type File Transfer Protocols without using flow control The 128 byte option allows remote users with slower modems to stop your transmitted data from scrolling off their screens When remote users send your computer an XOFF lt Ctrl S gt and you stop transmitting the data in transit doesn t exceed the size of their screen S16 Bit mapped register See the beginning of this appendix for information about setting bit mapped registers For testing see Chapter 15 Testing Bit Value Result 1 2 Dial Test 2 4 Test pattern 3 8 Remote digital loopback S18 Test timer for software initiated loopback testing amp Tn disabled when S18 is set to 0 Used to set the duration of testing in seconds before the Business Modem automatically times out and terminates the test A 8 APPENDIX A S REGISTERS Register Default Function S19 0 Sets the duration in minutes for the Inactivity Timer The timer activates when there is no data activity on the R232 interface and at the timeout the Business M odem hangs up S19 0 disables the timer 21 10
139. on The modem negotiates only for V 42bis compression and disables M NP Level 5 M NP5 compression Use this setting to transfer compressed files amp Ln Line type amp LO Normal amp Mn Enable ARQ error control protocol Both your modem and the remote device must use the same protocol amp MO Normal mode no error control Due to the nature of phone line channels this is never recommended for calls above 2400 bps amp M4 Normal ARQ mode If an ARQ connection isn t made the modem operates in Normal mode as though it were set to amp M 0 amp Nn Sets fixed link speed amp Nn amp UN Sets highest and lowest link speeds n 1 n 1 16 Variable rate The modem negotiates with the remote device for the highest possible connection rate depending on the capabilities of the remote device Fixed rate The modem connects only if the remote device is operating at the same rate You can use this feature to filter out calls at other than a specific rate for security or other reasons The connection rate must always be lower than or equal to the serial port rate n 1 300 bps n 2 1200 bps n 3 2400 bps n 4 4800 bps n 5 7200 bps n 6 9600 bps n 7 12000 bps n 8 14400 bps n 9 16800 bps n 10 19200 bps n 11 21600 bps n 12 24000 bps Ampersand amp Command Set B 9 Command Function n 13 26400 bps n 14 28800 bps n 15 31200 bps n 16 33600 bps n 17 28000 bps n 18 29333 bps n 19 30666 bps n 20 32000 bps n 21 33333 bp
140. onnection If TCP IP Protocol is NOT listed move to the next section To install TCP IP perform the following actions 1 Select Start Settings Control Panel 2 Double click Network 3 On the Protocol tab click Add and select the TCP IP protocol from the a Uu RR WN HB list To configure the Business M odem for a PPP connection perform the following actions Go to Start Programs Accessories Dial Up Networking Click New Select the Server tab and select PPP in the Dial up server type box Select TCP IP Deselect NetBEUI and IPX If you are connecting to an ISP uncheck Enable PPP LCP Extensions If you are connecting to another Windows NT system Check Enable PPP LCP Extensions Configuring a SLIP connection 7 Select Enable software compression 8 Specify an IP address by clicking TCP IP settings a u A WN HB If your ISP Do this Gives you a specific IP address Click Specify an IP address and enter the IP address provided by your ISP Does not give you a specific IP address Click Server assigned IP address After you specify an IP Address specify server assigned name server addresses if needed If your ISP Do this Gives you specific name server Click Specify name server addresses and addresses enter the server address es provided by your ISP Does not give you specific name Click Server assigned server addresses server addresses The following steps explain how to configure Windows NT
141. or drop the computer s or terminal s DTR signal The modem responds OK V PWn Assign the password in account n in your modem s security account as your Autopass password Octothorpe Command Set Command Function Display the help panels for the octothorpe command set CID n Controls the caller ID settings CID 0 Disable caller ID detection and reporting CID 1 Enable caller ID with formatted output CID 2 Enable caller ID with unformatted output CID 3 Enable caller ID with formatted output and name suppressed CID 4 Enable caller ID but do not transmit the information to your computer retain it in the modem s memory CID Display the current caller ID settings CID Display the caller ID actions that are available e 9 FLOW CONTROL TEMPLATE Hardware Flow Control The table below lists the Hardware flow control template To load this template send arsri to your modem NVRAM Options Setting Description Handshake option BO ITU T answer sequence Transmitter Cl Enabled Command mode echo El Enabled Online local echo F1 Disabled Training tone volume L2 M edium Speaker control M1 ON during dial through connect Result codes Q0 Enabled Verbal or numeric V1 Verbal result codes result codes Result code subset X7 Extended Includes all codes except VOICE Protocol response am
142. ost using Dial Security Once a connection is made follow the instructions for beginning a remote access session as described in Chapter 10 Accessing and Configuring the Business M odem Remotely When remote access has been granted use the AT S command to access the Dial Security accounts See Maintaining Security Accounts section earlier in this chapter To view the security account information use AT110 M ake any configuration changes and execute them immediately by entering arsc2 To end the remote session and reactivate Dial Security on the host reset the host device by issuing atz 10 10 CHAPTER 10 DIAL SECURITY WARNING If you do not use the ATZ command to end a remote access A session Dial Security will remain disabled at the host and anyone dialing in to the host for remote access will have access to the ATI10 screen and all Dial Security accounts eee e t e FLOW CONTROL This chapter contains information about a Hardware and software flow control wm Received data flow control m Transmit data flow control Overview The Business Modem has two buffers one for data transmitted from your computer and one for data received from the phone line Flow control provides a system for stopping and starting transmission depending on how full the buffers are Flow Control s purpose is to prevent overfilling the buffers which may cause data to be lost We recommend that you use hardware flo
143. p Networking or receiving RAS errors please contact M icrosoft Technical support Macintosh p Handshaking Cable This section explains how to configure your modem for use with M acintosh computers There are many ways to configure your M acintosh to use the Internet Consult your Macintosh documentation for more information Use a hardware handshaking cable to connect your modem to the M acintosh System Configuration Accessing the Internet gt Macintosh 230K High Speed script installation Installing the script Macintosh 1 13 Also if you aren t using AppleTalk amp Remote Access ARA set AppleTalk to Inactive in Chooser The modem initialization string should be ar amp rispo For instructions about how to set up your Macintosh communications software package see the software installation instructions that came with the software Accessing the Internet through an ISP requires the following software m MacTCP or Open Transport TCP IP from the Control Panels menu which has probably already been installed on your M acintosh m SLIP or PPP dialing software You can find public domain PPP dialers such as M acPPP FreePPP on the Internet To enable the 230K DTE support for the Business M odem and 25 mhz Business M odem you first must install the M acintosh 230K High Speed Script and then configure Open Transport PPP Download the USRARA HQX file This file can be found on the internet
144. p A3 Full protocol codes codes Serial port rate select amp B1 Serial port rate fixed higher than connect rate Carrier Detect amp C1 Normal operations Data Terminal REady amp D2 Normal operations Guard tone amp G0 U S Canada Transmit data amp H1 Hardware flow control hardware flow control Record data software amp IO Disabled flow control Analog data amp K1 Enabled compression Normal lines amp LO Normal lines C 2 APPENDIX C FLOW CONTROL TEMPLATE NVRAM Options Setting Description Error control amp M 4 Normal error control Link rate select amp NO Variable Pulse dialing type amp PO U S Canada Record data hardware amp R2 Enabled flow control Data Set Ready amp S0 Always on Remote Digital amp T5 Deny RDL Loopback RDL Break handling amp Y1 Clear buffer send immediately Stored telephone amp Z0 9 0 Blank number Caller ID CID 0 Caller ID disabled Word length 8 Parity 0 None DTE rate Kbps 19 2 Detected by each modem from the AT prefix of the amp W command that writes your defaults to NVRAM Set your software to the desired word length parity and serial port rate defaults before sending the modem the AT amp W string Software Flow control C 3 Software Flow control The table below lists the Software flow control template To load this template send arsr2 to the modem
145. phone number you saved type ATDS2 gt Displaying S Register Value Information Saving a Command String to NVRAM Working with Flash Memory 5 3 If the call requires a special setting insert it in the command before the DSn command In this example amp M 0 no error control comes before DS2 Type AT amp MODS2 The AT amp Zn s command functions differently when Dial Security is enabled See Chapter 11 Dial Security for more information For your modem to Command View the contents of a particular S Register ATSrI where r is the number of the S Register Example Sending arso will allow you to view the contents of Register S0 For your modem to Command Store a command string in NVRAM The command ate zc string string can be up to 30 characters long spaces do not count This command is used so that you can call another modem without loading your communications software Display the stored command string AT amp ZC Working with Flash Memory The Business M odem permanently stores three configuration templates or prepared sets of commands in Flash memory You can use the amp Fn command to load one of the three configuration templates from Flash memory into current memory To load this configuration template into current memory Command No flow control low performance AT amp FO Hardware flow control AT amp F1 Software flow control AT amp F2 Example Sending ar r1 to your mo
146. pports LAPM error control 1200 bps and higher Levels 2 3 and 4 error control level 5 data compression 1200 bps and higher Asymmetrical mode at 16 8 14 4 12 kbps 9600 7200 4800 bps 450 300 bps back channel Data compression 1200 bps and higher Digital and remote digital loopback testing Your Business Modem provides Group Ill compatibility when controlled by Class 1 or Class 2 0 fax software In addition your Business Modem adheres to the following standards This TIA EIA 578 TIA EIA 592 ITU T V 17 ITU T V 29 ITU T V 27 ter ITU T V 21 Supports Service Class 1 Asynchronous Facsimile DCE Control Standard Service Class 2 0 Asynchronous Facsimile DCE Control Standard 14 4 12 kbps 9600 7200 bps 4800 2400 bps 300 bps Additional Specifications Serial Ports This feature Technical Specifications E 3 Supports Supported serial port rates 230400 115200 57600 38400 19200 9600 4800 2400 1200 and 300 bps Adaptive Speed Leveling ASL 21600 19200 16800 14400 12000 9600 7200 and 4800 bps Serial port connector DB 25 Communications channel Full or half duplex on 2 wire phone lines demand driven high speed turnaround in HST mode symmetrical speeds in V 32 bis Data format Binary serial defaults to 8 bit word length no parity and 1 stop bit Word Length Parity 1 Bit Stop Bits 7 Even odd mark space 1 7 None 2 8 None 1 Flow
147. r S28 m f you are attempting to make a connection using HST modulation make sure that the modem at the other end of the line is HST compatible V 32 terbo compatible at 14 4 Kbps V 32 compatible at 9600 bps V 22 bis compatible at 2400 bps Bell 212A compatible at 1200 bps or Bell 103 compatible at 300 bps m f none of the above corrects the problem it s likely that the quality of the phone connection is poor The variable quality of phone line connections may be due to any number of conditions in the phone service s equipment or the current environment Try several calls and if you still can t get through try calling another device If the second device accepts your call the problem may lie with the device you first tried to call Errors during software download Try running the SDL program or performing the XM ODEM file transfer at a slower serial port rate If your computer doesn t have a 16550 UART set your communications software to use a slower serial port You can also try running the program on a different PC An idiosyncrasy of an off brand PC or an uncommon version of DOS may lock up the SDL program If You Still Have Problems The problems described above are by far the most common ones that users encounter If the suggestions we ve given don t clear up your difficulties try the following 1 Review the Getting Started Guide carefully to see if you ve missed something 2 Call or visit your dealer Chances are t
148. r types include Extended Industry Standard Architecture EISA and Microchannel Architecture M CA A number that must be assigned to devices that plug in to your computer s expansion bus Internet Protocol Novell s Internet Packet Exchange protocol See interrupt request See Industry Standard Architecture International Telecommunication Union Telecommunication sector Formerly referred to as CCITT An international organization that defines standards for telegraphic and telephone equipment For example the Bell 212A standard for 1200 bps communication in North America is observed internationally as ITU T V 22 For 2400 bps communication most U S manufacturers observe V 22 bis A switch composed of pins and a shunt The shunt s position on the pins determines the jumper setting Kilobits per second or thousand bits per second See Link Access Procedure for Modems Link Access Procedure for Modems an error control protocol incorporated in ITU T Recommendation V 42 Like the MNP and HST protocols LAPM uses cyclic redundancy checking CRC and retransmission of corrupted data ARQ to ensure data reliability local echo MB Microcom Networking Protocol MNP MI MIC MNP modem Nonvolatile Random Access Memory NVRAM NVRAM online fallback A modem feature that enables the modem to send copies of key board commands and transmitted data to the screen When the modem is in Command mode not online to anoth
149. ring detected 172 RING C Incoming distinctive ring detected 173 TING D Incoming distinctive ring detected Wait for another Dial Tone W Business Modem continues dialing as soon as it detects another dial tone Requires X3 or higher Wait for an answer Business Modem continues dialing when it detects 5 seconds of silence on the line Requires X3 or higher D 2 APPENDIX D RESULT CODE MEANINGS AND SETS Result Codes Sets for Xn Values Result Codes X0 X2 X3 X5 X6 0 OK 1 CONNECT 2 RING 3 NO CARRIER 4 ERROR 5 CONNECT 1200 6 NO DIAL TONE 7 BUSY 8 NO ANSWER 10 CONNECT 2400 11 RINGING 12NOICE 13 CONNECT 9600 18 CONNECT 4800 20 CONNECT 7200 21 CONNECT 12000 25 CONNECT 14400 43 CONNECT 16800 85 CONNECT 19200 91 CONNECT 21600 99 CONNECT 24000 103 CONNECT 26400 107 CONNECT 28800 151 CONNECT 31200 155 CONNECT 33600 171 RING A 172 RING B 173 RING C 174 RING D Functions Wait for 2nd Dial Tone W Wait for Answer eete e e e e TECHNICAL INFORMATION Technical Specifications Modulation Your modem uses multiple standard data communications protocols and is also compatible with many nonstandard schemes The following schemes are supported This modulation v 90 x2 ITU T V 34 V FC V 32 terbo
150. rolling Link Speeds Limiting the Highest Possible Connect Speed Limiting the Lowest Possible Connect Speed Limiting a Range of Possible Connect Speeds amp N and amp U Command Values Setting DTE Rate to 230 Kbps ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY Overview Setting Up Remote Access At the Host Business Modem Other Remote Access Commands Accessing the Host At the Guest Device FLOW CONTROL Overview Hardware and Software Flow Control Hardware Flow Control Software Flow Control Received Data Flow Control Transmit Data Flow Control HANDSHAKING ERROR CONTROL DATA COMPRESSION AND THROUGHPUT Handshaking Selective Reject V 90 Capabilities Other Protocols Lower speed V Protocols Error Control Error Control Commands V 42 Error Control MNP Error Control Error Control and Flow Control Data Compression V 42bis versus MNP5 Data Compression Getting Maximum Throughput Maximum throughput results when cccceeeceecssecsereeesseeesereeesaes 12 9 DISPLAYING QUERYING AND HELP SCREENS Overview Querying Displaying Help TESTING THE CONNECTION Overview Testing the Business Modem using AT amp Tn Analog Loopback Testing Stopping a Test AT amp TO ATS18 Remote Digital Loopback Testing AT amp T6 AT amp T7 Granting a Digital Loopback Test Request AT amp T4 Canceling All Digital Loopback Test Requests amp T5 Testing Using a Built in Test Pattern ATS16 Ending Testing Th
151. rsion of the modem software and information INF file from the 3Com U S Robotics Web site http w w w usr com home online This file Does this The modem software Contains software that contains new feature updates The INF file Helps your computer work more effectively with your modem Installing the Latest See Chapter 3 Upgrading your Modem for information about upgrading Software your Business M odems software Accessing Your This section explains how to set up your modem to access the Internet or Internet Service remote Local Area Networks LANs using Windows 95 98 Dial Up Provider Networking To Access Internet Service Providers ISPs or remote LANs you must do the following Windows 95 98 1 3 Step One Determine if Dial Up Networking is Installed 1 Click Start Settings Control Panel 2 On the Control Panel double click on Network The Network widow will appear If Dial Up Adapter Do this Is listed Go to the section Installing TCP IP Support to install Dial Up Networking Is not listed Go to Step 3 3 Return to the Control Panel and double click on Add Remove Programs to open the Add Remove Programs Properties window 4 Click Windows Setup tab 5 Double click on Communications The following window appears Communications x To add or remove a component click the check box Ashaded box means that only part of the component will be installed To see what s included in a compon
152. rt command is called XON for transmit on and the stop command is called XOFF transmit off You can change the characters used See Registers 22 and S23 in Appendix B Alphabetic Command Summary Received Data Flow Control 11 3 Received Data Flow Control Flow control settings are controlled by the AT amp Rn and AT amp ln commands The default settings are amp R2 amp I0 Use the following table for more information about setting the flow control For your modem to Command Pause before sending CTS signal after receiving the AT amp RO Request to Send RTS Ignore the RTS signal AT amp R1 amp R1 is required if your computer or software does not support RTS Enable hardware flow control AT amp R2 The Business M odem sends data to your computer only upon receipt of the RTS signal Disable software XON XOFF flow control AT amp IO Default Recommended for non ARQ Normal mode calls see AT amp I5 While the Business M odem is online the only characters it recognizes are the escape code Enable software XON XOFF flow control Use in ARQ AT amp I1 mode only Keep in mind that the XON XOFF characters sent to the remote computer may interfere with XON XOFF signaling between the remote computer and remote device see AT amp I2 Force the Business Modem to act on your XON XOFF AT amp I2 commands but remove them from the data stream instead of passing them to the remote computer This ensur
153. s n 22 34666 bps n 23 36000 bps n 24 37333 bps n 25 38666 bps n 26 40000 bps n 27 41333 bps n 28 42666 bps n 29 44000 bps n 30 45333 bps n 31 46666 bps n 32 48000 bps n 33 49333 bps n 34 50666 bps n 35 52000 bps n 36 53333 bps n 37 54666 bps n 38 56000 bps n 39 57333 bps amp Rn Received data RTS hardware flow control amp RO Delay Clear to Send CTS response after Request to Send RTS amp R1 Ignore RTS This setting is required if your computer or terminal or software does not support RTS B 10 APPENDIX B ALPHABETIC COMMAND SUMMARY Command Function amp R2 Enable hardware flow control of received data The modem sends data to the computer only upon receipt of the RTS signal amp Sn Send the computer a Data Set Ready DSR signal via the EIA 232 interface Data Set is industry jargon for modem amp SO DSR is always ON override amp S1 In Originate mode Send DSR after dialing on detection of the remote device s answer tone In Answer mode Send DSR after sending an answer tone amp S2 When Carrier is lost send a pulsed DSR signal with Clear to Send CTS following Carrier Detect CD This option is for specialized equipment such as automatic callback units amp S3 Same as amp S2 but without the CTS signal amp S4 Send the computer DSR at the same time as CD amp S5 Send DSR normally and follow CTS with CD amp Tn Test the modem amp T0 End testing amp T1 Enter Analo
154. s making a data connection using an error control protocol Off Is making a data connection without using an error control protocol AA On Is ready to accept calls Blinking Has detected an incoming call Off Is not ready to accept calls OH On Has control of the line Off Does not have control of the line TD On Is transmitting data Off Is not transmitting data RD Flashing Is sending data to your computer Off Is idle MR On Is powered on and ready or is receiving RS232 DSR signal Flashing Is retraining with a remote device or is in Test mode Off Is powered off H 2 APPENDIX H VIEWING LEDS This LED Status Means your Business Modem TR On RS232 mode has detected DTR signal USB mode has detected successful USB registration Off RS232 mode has not detected DTR USB mode has not detected successful USB registration CD On Has detected a carrier from a remote device or carrier detect has been forced on Off Has not detected a carrier RS On Has detected the Ready to Send RTS signal from your computer Off Has not detected the RTS signal from your computer CS On Is sending your computer the Clear to Send CTS signal Off Is not sending your computer the CTS signal S REGISTERS S Registers S Registers Their Functions and Default Settings Register Default Function SO ets the number of rings on which to answer in Auto Answer mode S0 0 disables Auto Answer S0 1 enables Auto Answer and the Business M odem ans
155. second before typing any data When you type the modem will either hang up or stay on line depending on how you set S14 Repeat command If you include the repeat command in the Dial string the modem will dial the number and wait 60 seconds for a carrier If the line is busy the modem will pause for 2 seconds and then redial The modem makes a maximum of 10 attempts Al Reexecute the last issued command DO NOT type AT or press Enter Repeat the last issued command until canceled by pressing any key DO NOT type AT or press Enter AT Attention prefix informs a modem that a command is coming AT must precede all commands except A A gt and Force a modem to answer when it is not receiving an incoming call B 2 APPENDIX B ALPHABETIC COMMAND SUMMARY Command Function Bn Set handshaking options B1 Bell answer tone This setting selects HST modulation but use it only if the modem is not required to answer V 34 type calls Cn Enable or disable the transmitter co Transmitter disabled for receiving only C1 Transmitter enabled With the exception of the Dial options modems ignore any commands issued after D in the same command string Command Function Dn Dial a phone number and issue other optional commands The numbers 0 9 are accepted The maximum number of characters allowed is 36 including the AT prefix punctuation and spaces Optiona
156. software initiated loopback testing amp Tn disabled when S18 is set to 0 Used to set the duration of testing in seconds before the Business M odem automatically times out and terminates the test Sets the duration in minutes for the Inactivity Timer The timer activates when there is no data activity on the phone line and at the timeout the Business Modem hangs up 519 0 disables the timer Sets in 10 millisecond units the length of breaks sent from khe Business Modem to the computer or terminal Applies to ARQ mode only Stores the ASCII code for the XON character Stores the ASCII code for the XOFF character SERES Sets the duration in 20 millisecond units between pulsed DSR signals when the Business M odem is set to amp S2 or amp S3 The default is 3 seconds Sets DTR recognition time in I0 millisecond units SEE Bit mapped register See Chapter 1 Using the AT Command Set for instructions about setting bit mapped registers Bit Value 0 1 Result Enable ITU T V 21 modulation at 300 bps for overseas calls In V 21 mode the Business M odem answers both Bell 103 and V 21 calls but only originates V 21 calls Enable unencoded non trellis coded modulation in V 32 mode this option is part of the ITU T V 32 recommendation but is rarely used Disable V 32 modulation used for testing HST modulation S Registers 1 5 Register Default Fu
157. st ringing signal while the call is being connected If the remote device has V 34 capability Business M odem use a line probing technique to determine the highest speed possible under current line conditions then they complete the connection If the remote device does not have V 34 capability the Business M odem listens to the device s answer tones to identify the standard rate at which the remote device is operating and then adjusts to that rate When the Business M odem answers a call it sends out a series of answer tone signals until both devices negotiate the best connection rate V 90 Capabilities The Business Modem has V 90 capabilities The Business M odem can dial into V 90 servers to establish speeds up to 56K downstream For your modem to Command Enable V 90 ATS58 5 0 Default Disable V 90 ATS58 5 1 Other Protocols x2 Fast Class V FC Handshaking X2 client modems can receive data at speeds up to 56 kbps and send data at V 34 speeds To use x2 the client x2 modem must connect to a server x2 modem If clients attempt to connect to ISPs that do not use x2 the client modem will negotiate the next available modulation For example an X2 client modem calling into an ISP that only supports V 34 the modem will only negotiate the highest v 34 connection rate The maximum V 34 connection speed is 33 6 kbps After trying V 34 the Business M odem tries for the fastest possible V Fast Class 28 8 Kbps con
158. sword the account you set up Example Sending atsv pw3 will assign the password as an Autopass password for account 3 c Check to see that you set your Autopass password correctly by using the ATI10 command Your Autopass password appears beside AUTOPASS PASSWORD if you have done all the steps correctly d Oncethe Autopass password is set enable your Business M odem s Dial Security For your modem to Command Enable Dial Security ATS53 0 1 CAUTION If you do not follow an S Register setting with amp W the setting will be retained only until the next reset or power off Configuring Dial Security Remotely 10 9 If Dialback is enabled at the host Business M odem s site set your modem to answer the host Business M odem when it dials back For your modem to be set Command To answer the Dialback call ATSO 1 4 Call the host After the call ends you can disable Auto Answer For your modem to Command Disable Auto Answer ATSO 0 Configuring Dial Security Remotely gt The host administrator can configure the host s security settings remotely At the host device you must have previously enabled remote access and assigned a remote access password that allows view and change privileges see Chapter 10 Accessing and Configuring the Business Modem Remotely You may want to use your administrative password as your remote access password Dialing In From the Remote Site From the remote site connect to the h
159. synchronous M ode Example Sending av wa4 allows your modem to operate in Normal Mode is an ARQ connection can t be made Error control is available for calls at 1200 bps and above It can be disabled although high speed calls 9600 bps or higher should always be under error control The operations defined in an error control protocol include Establishing compatibility Formatting data frames Detecting errors using Cyclic Redundancy Checking CRC Retransmitting corrupt data frames The Business M odem is set at the factory to try for an error control connection and if that isn t possible to proceed with the call in Normal mode This means that amp M 4 is set V 42 Error Control MNP Error Control Error Control and Flow Control Error Control 12 7 The Business M odem first tries for a V 42 connection then an MNP connection The following information is based on the Business M odem s setting of amp M 4 This international standard includes a two stage hand shaking process m A Detection phase that is based on an exchange of predefined characters m A Link Access Procedures for Modems LAPM Negotiation phase during which the devices identify their capabilities concerning maximum data block size and the number of outstanding data blocks allowed before an acknowledgment is required The Microcom Networking Protocol M NP is supported by the ITU T V 42 Recommendation M NP is based on special protocol frames
160. t codes when answering S Display help screens for the S Registers Sr n Set S Register value r is any S Register n must be a decimal number between 0 and 255 Sr b n Set a bit mapped register r is the S register b is the bit and n is O off or 1 on Sr Query contents of S register r p See Appendix A S Registers for a listing of all the S Registers Command Function Vn Display result codes in words or numbers VO Display result codes in numeric form v1 Display result codes in verbal form Xn Control the amount of information displayed in the result codes The default is X7 all codes except 12 VOICE Ampersand amp Command Set B 5 Command Ignore Dial Tone Microsoft default Business M odem default Z Software reset Pressing the RESET button on the rear panel of the modem resets the modem to the amp FO configuration template no flow control Ampersand amp Command Set Command Function amp Display help for the ampersand amp command set amp An Enable or disable the display of additional result code subsets Also see the Xn command amp A0 Do not display ARQ result codes amp A1 Display ARQ result codes amp A2 In addition to ARQ result codes display HST V 32 V FC or V 34 modulation indicator amp A3 In addition to ARQ and modulation indicators display an error control indicator LAPM HST M NP or NONE and a data compr
161. t the mainframe also needs to be set to ATQ1E0 Bad faxes or can t fax a M ake sure the fax software is set to use Class 1 fax Refer to your fax software s manual If you use memory resident programs TSRs Terminate and Stay Resident programs or disk caching programs they may be interfering Try disabling them before you run your communications software Both devices exchange carrier signals but fail to establish a communications link M ake sure the Business M odem is in the correct mode fax or data depending on whether the connection is to be made with a facsimile device or a data device See Chapter 2 Modes of Operation for information on switching between Fax and Data modes M ake sure the proper bit rate word length parity and number of Stop bits have been selected Send ATI4 and check to see that your modem is at the correct Bn setting to connect with either an HST modem BI setting or V modem BO setting M ake sure that your Business M odem s connection rate setting amp Nn is correct for the call If the connection rate is locked at a speed amp N1 amp N14 different from the calling modem s the Business M odem hangs up The default setting of amp NO variable link operations allows the two modems to negotiate the highest possible connection rate If your modem is attempting to answer a V 32 call you may need to lengthen the extra V 32 answer tones See Appendix B Alphabetic Command Summary unde
162. te system Command The modem sends a copy of the data to the screen Online ATFO local echo ON half duplex No copy of the data is displayed on screen Online echo OFF ATF1 default full duplex Example Sending arro will allow you to see what you are typing in the display window You may see the term duplex used in place of online local echoing although the term is not technically accurate 3 4 CHAPTER 3 MODES OF OPERATION Data and Fax Modes Once you are in Command Mode you can initialize the modem in Data or Fax mode Fax operations require facsimile compatible communications software that can send or receive Group III faxes Follow the instructions in your fax software manual The modems default operating mode is Data Mode Most fax software automatically switches the device to Fax mode when you run the program and resets the device to Data mode when you exit the program If you want the modem prepared to Mode Command Make calls to and receive calls from other Data Mode AT FCLASS 0 modems Make calls to and receive calls from analog Fax Mode AT FCLASS 1 facsimile devices such as fax modems and Class 1 Fax M ode fax machines or AT FCLASS 2 0 Class 2 0 Fax Mode Example Sending at rciass 1 allows you to receive faxes from fax machines Class 1 and Class 2 0 Fax Modes refer to standards set by the Electronic Industries Association Telecommunications Industry Association Class
163. ted under documents Select CIB Interference Handbook or CIB Telephone Interference Bulletin Any changes or modifications not expressly approved by the party responsible for compliance could void the user s authority to operate this equipment J 6 APPENDIX J WARRANTY IC Industry Canada A UL Listed Accessory This digital apparatus does not exceed the Class B limits for radio noise emissions from digital apparatus set out in the interference causing equipment standard entitled Digital Apparatus ICES 003 of Industry Canada Cet appareil num rique respecte les limites de bruits radio lectriques applicables aux appareils num riques de la Classe B pr scrites dans la norme sur le mat riel brouilleur Appareils Num riques NMB 003 dict e par l Industrie Canada The Industry Canada label identifies certified equipment This certification means that the equipment meets certain telecommunications network protective operational and safety requirements The department does not guarantee the equipment will operate to a user s satisfaction Before installing this equipment users should ensure that it is permissible to be connected to the facilities of the local telecommunications company The equipment must also be installed using an acceptable method of connection In some cases the inside wiring associated with a single line individual service may be extended by means of a certified connector assembly telephone extension cor
164. ters are in the form of Srb n where r is the bit mapped register b is the bit n is O off or 1 on The modem displays the value of an S Register as a decimal value between 0 and 255 The modem however understands the decimal value as a collection of binary digits bits How bits are mapped to decimal values Bits can be mapped into decimal values Each bit can be either on 1 or off 0 Eight bits create 256 unique combinations of 1s and Os Each of the eight bits can be assigned a number corresponding to its position bbbbbbbb 76543210 Also each bit can be assigned a value corresponding to its number Bit Value 7 27 128 6 26 64 5 2 32 4 24 16 3 23 8 2 22 4 1 2222 0 20 1 A 2 APPENDIX A S REGISTERS Converting Bits to Decimal Values Starting with a string of eight bits assign each 1 bit a value based on its position Add the values to come up with the final decimal value Here s an example of how bits are converted to decimal values 01001111 Converting Decimal Values to Bits Convert decimal values to bits by finding the largest decimal equivalent that is less than the decimal value Subtract the decimal equivalent and mark the equivalent bit 1 Continue until the decimal value is zero See the example below 113 113 64 49 01 49 32 17 011 17 16 1 0111 1 1 0 01110001 Setting Bit Mapped S Registers You can set bit mapped S Registers using
165. the number of log in attempts available to the remote user A setting of zero allows no log in attempts disabling remote access Example Sending ats41 1 w allows for 1 log in attempt by a remote user Set one or two remote access passwords You can set two passwords to allow different levels of access to each Business M odem Use this command to assign a To allow guest users to remote access password View the Business M odem s configuration AT amp PO password View and change the Business M odem s AT P1 password configuration Example Sending atspi corn Will allow a remote user to log in with the password corn The user can view and change the Business M odem s configuration Remote access passwords can be up to eight alphanumeric characters long and are not case sensitive Other Remote Access Commands Aa The table below is a list of remote access configuration commands For your modem to Command Display a view only password AT P0 Display a view and change password AT P1 Erase a view only password AT PO Erase a view and change password AT P1 Disable remote access entirely ATS41 0 Example Sending arsP1 will erase the view and change password WARNING If you erase the P1 password without disabling remote access using ats41 0 anyone could access the Business Modem and change its configuration Accessing the Host At the Guest Device The guest device requires no configuration to a
166. the three configuration templates that are stored permanently in read only memory Appendix C Flow Control Templates lists the settings for each template To load a template into current memory enter AT amp Fn To write a template to NVRAM enter AT amp Fn amp W amp FO is always loaded into memory at power on or when the RESET button is pressed amp FO Load No Flow Control template settings amp F1 Load Hardware Flow Control template settings amp F2 Load Software Flow Control template settings amp Gn Set guard tones for international calls amp GO No guard tone Use this in the United States and Canada amp G1 This sets a 550 Hz guard tone and is used in some European countries amp G2 This sets an 1800 Hz guard tone and is used in the U K and some Commonwealth countries amp G2 requires the BO setting amp Hn Transmit data flow control Prevents the modem s buffer for data transmitted to the modem by its attached computer from overflowing amp HO Disable transmit data flow control Ampersand amp Command Set B 7 Command Function amp H1 Use hardware flow control Requires that your computer and software support Clear to Send CTS at the EIA 232 interface amp H2 Use software flow control Requires that your software support XON XOFF signaling amp H3 Use both hardware and software flow control If you are unsure about what your equipment supports select this option amp
167. tore the original configuration using the AT C1 command the first prompt is restored assuring you the original configuration is intact Quitting a Remote Access Session If you want to quit the remote access login before you have entered the password return online by pressing lt Ctrl gt C or typing ATO After you ve entered the password you can quit by sending one of these commands To end the remote access session Command And keep the connection ATO And end the connection ATH End the connection and reset the host modem ATZ Before you disconnect issue the ATIb command to the remote modem and check its S41 setting Make sure S41 is set for a value of 1 or greater If S41 is set to 0 when you disconnect you will not be able to access the remote modem again To prevent this send ATS41 1 amp W before you disconnect 9 8 CHAPTER 9 ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY eee e t e DIAL SECURITY This chapter contains information about a Setting up Dial Security a Maintaining security accounts m What the guest user needs to do wm Configuring dial security remotely Overview Dial Security is designed to protect networks and data centers from unauthorized access You should be familiar with these terms before you continue Local The device that is directly connected to the computer you are using Remote The device at the other end of a telephone connection Host
168. tween transmitted characters may vary Because the time lapses between transmitted characters are not uniform the receiving modem must be signaled as to when the data bits of a character begin and when they end The addition of start and stop bits to each character serves this purpose A feature in modems enabling them to answer incoming calls over the phone lines without the use of a telephone receiver A feature in modems enabling them to dial phone numbers over the phone system without the use of a telephone transmitter A general term for error control protocols which feature error detection and automatic retransmission of defective blocks of data See HST MNP and V 42 The number of discrete signal events per second occurring on a communications channel Although not technically accurate baud rate is commonly used to mean bit rate A 0 or 1 reflecting the use of a binary numbering system only two digits Used because the computer recognizes either of two states OFF or ON Shortened form of binary digit is bit See binary digit A technique that lets one decimal number in this case a number between 0 and 255 stand for up to 8 separate binary settings The number of binary digits or bits transmitted per second bps Communications channels using telephone channel modems are established at set bit rates commonly 300 1200 2400 4800 9600 14400 and 28800 The bits binary digits per second rate A memory ar
169. unications may refer to the suppression of the online Local Echo Signal flow in both directions but only one way at a time In microcomputer communications may refer to activation of the online Local Echo which causes the modem to send a copy of the transmitted data to the screen of the sending computer A sequence that two modems undertake while connecting to agree on the parameters of the conversation that will ensue During handshaking the modems negotiate the speed of the connection whether error control and data compression will be used and in what form and so forth A form of flow control that uses electronic signals to start and stop the flow of data HDLC High Speed Technology HST Hz Hertz Industry Standard Architecture ISA interrupt request IRQ IP IPX IRQ ISA ITU T jumper Kbps LAPM Link Access Procedure for Modems LAPM See High Level Data Link Control 3Com proprietary signaling scheme design and error control protocol for high speed modems HST incorporates trellis coded modulation for greater immunity from variable phone line conditions and asymmetrical modulation for more efficient use of the phone channel at speeds of 4800 bps and above HST also incorporates M NP compatible error control procedures adapted to asymmetrical modulation A frequency measurement unit used internationally to indicate one Cycle per second The most common type of computer expansion bus Othe
170. ur software may use terms such as locked serial port fixed rate or autobaud variable rate Set the serial port To allow your modem rate as Command To change its serial port rate to match the Variable AT amp BO connection rate To always communicate with an attached Fixed AT amp B1 Default device at the rate at which you have set the terminal or software regardless of the connection rate For the greatest throughput set the serial port to 115200 57600 or 38400 bps for high speed calls and to at least 9600 bps for 2400 bps calls To shift its serial port rate to a rate that you specify using your communications software for example 38 4 Kbps when the Business Modem connects in ARQ mode If the connection is not under error control the Business Modem behaves as if it was set to amp BO and switches its serial port rates to match the connection rate of each call To implement this feature first set your software to the desired rate Then send AT amp B2 amp W to the modem The Business M odem stores the rate of the command in NVRAM along with the current settings The Business Modem checks NVRAM for the specified serial port rate each time it makes an ARQ connection When saving subsequent configurations to NVRAM be sure your software is set to your selected serial port rate so the Fixed for ARQ calls AT amp B2 and Variable for non ARQ calls when answering only See Chapter 13 Handsha
171. ve password WARNING Be sure to remember your administrative password If you enable Dial Security and then forget your administrative password you Modifying Accounts will be locked out of the Business M odem s dial security features You will need to restore the factory defaults This will erase ALL passwords and you will have to reconfigure all your accounts Set up guest user accounts Use the AT An command to set up guest user accounts in the same way you set up your administrative account You can set up nine guest accounts Refer to the figure in step 1 regarding information about formatting the AT An command After you have enabled the guest accounts make sure the guest users know their passwords and the log in procedure After you have set up an account you can modify each field independently If a field is to remain unchanged from its original setting just insert a comma as shown aTsa1 Y The command above allows the guest user to supply a dialback number that is different from the one stored in the original account record Enable Local Security WARNING If you do not enable Local Security the Dial Security settings will not be protected and other users will be able to change or erase them For your modem to Command Protect the administrative password local security ATS53 2 1 enabled You must use the amp W command to save the settings in NVRAM If you don t the next time you reset or power off t
172. w control If you do depending on your communications software you will also need to enable hardware flow control in your communications software 11 2 CHAPTER 11 FLOW CONTROL Hardware and Software Flow Control Hardware Flow Control Software Flow Control There are two kinds of flow control hardware and software Business Modems support both but your computer and communications software must also support the kind of flow control you choose Business M odems implement hardware flow control by detecting that a buffer is 9096 full and then interrupting the Clear to Send CTS signal to stop the flow of data When the buffer drops back to 5096 full the Business M odem sends CTS to restart the flow of data Business M odems implement software flow control by detecting that a buffer is 9096 full and then sending special characters in the data stream to stop the flow of data When the buffer drops back to 5096 full the Business M odem sends special characters in the data stream to restart the flow of data The problem with software flow control is that the characters used to stop Ctrl Q and start lt Ctrl gt S the flow of data can occur naturally in the data flow Enabling software flow control instructs the Business M odem to recognize and act on these characters even if they are not intended to control the data flow Using software flow control may prove satisfactory if you re transferring text files only The sta
173. ware handshaking cable to get the most reliable performance MUN DB 25 Connector Male A LN Macintosh O amp amp pnDN a4 ol a 000000000000 Gonnostar X ee J id W YYY Male ESAE MacPin MacPin Description ModemPin Modem Pin Description 1 Output Handshake 4 20 Request to Send and Data Terminal Ready 2 Input Handshake 5 Clear to Send 3 Transmit Data 2 Transmit Data Ground 7 Ground 4 8 Ground to Received Data 5 Received Data 3 Received Data E 6 Serial Ports Macintosh modem APPENDIX E TECHNICAL INFORMATION These are the signals generated or accepted by your modem s serial port Signal Ground Data Set Ready Clear to Send DB 25 Connector Female AVAY Y 2 Oo ala ot 8 12 15 17 Request to Send Received Data Transmit Data Chassis Ground Carrier Detected Speed Indicated Synchronous Transmitter Timing Synchronous Receiver Timing 20 Data Terminal Ready 22 Ring Indicate AVAYVYVYVY 24 Synchronous Transmitter Timing ASCII CHART eete Dec Hex Char Dec Hex Char Dec Hex Char Dec Hex Char 00 00 NUL 32 20 SP 64 40 96 60 01 01 SOH 33 21 65 41 A 97 61 a 02 02 STX 34 22 66 42 B 98 62 b 03 03 ETX 35 23 67 43 C 99 63 04 04 EOT 36 24 68 44 D 100 64 d 05 05 ENQ 37 25 69 45 E 101 65 e 06 06 ACK 38 26 amp 70 46 F 102 66 f 07 07
174. wers on the first ring Counts and stores the number of rings from an incoming call ores the ASCII decimal code for the escape code character Default character is A value of 128 255 disables the escape code ores the ASCII decimal code for the Carriage Return character Valid range is 0 127 ores the ASCTI decimal code for the Line Feed character Valid range is 0 127 ores the ASCII decimal code for the Backspace character A value of 128 255 disables the Backspace key s delete function ets the number of seconds the Business Modem waits for a dial tone ets the number of seconds the Business M odem waits for a carrier May be set for much longer duration if for example the Business M odem is originating an international connection ets the duration in seconds for the pause option in the Dial command and the pause between command reexecutions and A commands ets the required duration in tenths of a second of the remote device s carrier signal before recognition by the Business M odem 1 2 APPENDIX S REGISTERS Register Default Function SIO Sets the duration in tenths of a second that the Business M odem waits after loss of carrier before hanging up This guard time allows the Business M odem to distinguish between a line hit or other disturbance that momentarily breaks the connection from a true disconnect hanging up by the r
175. with arer4 you will get an ERROR result code There are two remote digital loopback options If you want to Command Send keyboard data to the modem and verify it when itis AT amp T6 returned over the phone lines and to your screen Have the modem send its internal test pattern and return AT amp T7 an error count to your screen Example Sending arete will verify keyboard data sent to the modem by returning it over the phone lines and displaying it on your screen Using AT amp T4 causes the Business Modem to grant a remote device s request for a remote digital loop back test Using AT T5 cancels atera and the Business Modem fails to acknowledge remote digital loopback test requests This is the default so that your Business M odem isn t subject to another user calling and tying up your Business Modem without your permission Testing Using Keyboard Data AT amp T6 1 Testing the Business Modem using AT amp Tn 14 7 Send AT amp MO amp N3S14 0 0 to prepare the Business M odem for testing This command disables error control fixes the connection rate at 2400 bps and makes the Business M odem return to command mode when you type the escape code 2 Establish a connection with the remote device 3 If you haven t already done so arrange with the remote user to cooperate with the test If necessary set the remote device to acknowledge the remote digital loopback request For example older modems need to be s

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