Auto-detect system and method for data communication
Contents
1. o 1 1 1 1 1 1 1 Least Sign Bit Start Bit ooooo o communication program in the receiving computer 14 may 5 553 271 9 not have any advance information as to which characters will be transmitted first from the transmitting computer 12 the need exists for the auto detect communication method according to the present invention in order to reliably detect the data word format being used as quickly as possible so that the information being transmitted is properly interpreted at the receiving computer 14 Referring to FIGS 3A 3D a set of flow chart diagrams which illustrate the AutoDetect Analyze method according to the present invention is shown The initial step in this method is a check to see if the Auto Detect feature is already running diamond 300 If this is the first time that the Auto Detect Analyze method 214 has been called for the current communication session then the Auto Detect engine will be initialized block 302 This initialization resets a predetermined data structure to an initial condition This data structure includes a set of counters which are initial ized to zero and a set of flag values as follows ADTotal for the total number of data words processed ADMix for the number of data words having odd parity using the least significant seven bits AD7o1 for the number of data words2. PP aera DN E character forming criteria must be received and tested Once 4 077 058 2 1978 Appell et Bet 364 200 both of these events have occurred then a data word format 4316283 2 1982 37094 18 determined from the results of this testing and the 4 425 664 1 1984 Sherman et al c 315 8 computer is configured to interpret and output characters 4 604 686 8 1986 Reiter et al 364 200 from the data stream in accordance with this data word 4 635 275 1 1987 Borg et al 2 22 2222 375 8 format setting The characters interpreted from the data 4 680 781 7 1987 Amundson et al 375 8 stream are also tested against a plurality of terminal emu 4 715 044 12 1987 Gartner seen 375 8 lation criteria until a character sequence has been detected 20 0d pr os ps won which is indicative of only one emulation standard 5 031 207 7 1991 Hesdahl et al 379 93 5 034 598 7 1991 Poland 235 435 11 Claims 7 Drawing Sheets U S Patent Sep 3 1996 Sheet 1 of 7 5 553 271 BEGIN RECEIVE REFILL 200 202 NO IS AUTO DETECT Fig 2 C Ie YS B N 1 210 READ COMM PORT 208 RECORD ERROR CAN YES REMOVE CHAR COMM ERRORS NO 212 04 206 0 216 AUTO DETECT ON AND TERMINAL EMULATION CARRIER RCVD ANALYZE 218 YES 214 PASS DATA AUTO DETECT TO EMULATOR ANAL ED U S Patent Sep 3 1996 Sheet 2 of 7 5 553 271 BEGIN 214 AUTO DETECT ANALYZE 300 15
3. AUTO DETECT ALREADY RUNNING NO START AUTO DETECT AND INITIALIZE ALL COUNTERS TO ZERO YES 306 304 YES STOP AUTO DETECT 8 ANY 302 FRAMING ERRORS NO 30 ADD SAMPLE SIZE RETURN GET NEXT 310 CHARACTER FROM SAMPLE 312 IS THERE AN ODD OF BITS IN LEAST SIGN 7 BITS OF CHAR YES INCREMENT ADMIX MEMBER Fig 3A 318 U S Patent Sep 3 1996 Sheet 3 of 7 5 553 271 314 IS THERE AN ODD OF BITS USING 8 BITS 320 INCREMENT nAD7o1 MEMBER 316 IS MOST SIGN BIT YES OF THE CHARACTER jr 322 INCREMENT ADHIGHBITS MEMBER 324 amp NO CHECKED ALL CHARS YES 326 HAVE ENOUGH CHARS NO BEEN RECEIVED AND ODD EVEN 328 MIX SUFFICIENT SET MOST SIGN YES BIT OF ALL CHARACTERS TO O U S Patent Sep 3 1996 Sheet 4 of 7 5 553 271 330 IS nAD7o1 0 2 YES SET COMMUNICATION PARAMETERS TO Zel 5 nAD7o1 nADTOTAL 336 SET COMMUNICATION PARAMETERS TO 7ol SET COMMUNICATION PARAMETERS TO 8nl STOP AUTO DETECT AND CONFIGURE PROGRAM FOR DETECTED PROTOCAL Fig 3C U S Patent Sep 3 1996 Sheet 5 of 7 5 553 271 342 IS ADMIX gt 0 AND ADMIX lt ADTOTAL NO 344 IS AD7o1 ADTOTAL 348 SET ADBESTGUESS AD_701 IS YES nAD7o1 0 350 SET ADBESTGUESS AD_7E1 SET 2 nADBESTGUESS DONT AD 8 1 Fig 3D
4. FIG 2 is an overall flow chart of the auto detect com munication method according to the present invention FIGS 3A 3E represent a set of flow chart diagrams which illustrate the Auto Detect Analyze method depicted in FIG 2 and an Auto Detect Output method in connection there with FIG 4 is a block diagram which illustrates the Terminal Analyze method depicted in FIG 2 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG 1 a diagrammatic representation of the auto detect data communication system 10 according to the present invention is shown In this regard FIG 1 illustrates two types of data communication between a transmitting computer 12 and a receiving computer 14 While computer 12 is labeled as the transmitting computer and computer 14 is labeled as the receiving computer it should be understood that both of these computers will be transmitting and receiv ing data during a communication session Thus the trans mitting label attached to computer 12 is used to signify the computer which is sending a data stream which the receiving computer 14 needs to be able to interpret in real time While the present invention is described in connection with the use of a serial data stream it should be appreciated that the present invention may be used with other forms of data streams such as parallel data streams The present invention is further described in connection with an asynchronous form of data transmission
5. it should also be understood that the present invention may be adapted for use with synchro nous forms of data transmission The first type of data communication illustrated in FIG 1 is one in which a conventional telephone system is used as the data transmission carrier or facility In this case the telephone system is represented by one or more public switching stations such as switching stations 16 and 18 Additionally each of the computers 12 14 will generally require its own communication interface device for convert ing the binary based signals used by a computer to the type of signal needed for transmission on a telephone network such as an analog based signal Accordingly FIG 1 shows the use of a modem modulator demodulator by each of the computers 12 14 as the communication interface device In this regard the modem 20 provides the interface between the transmitting computer 12 and the switching station 16 while the modem 22 provides the interface between the receiving computer 14 and the switching station 18 However it should be appreciated that the present invention is not dependent upon the type or model of interface and that other suitable communication interface devices may be employed 10 15 20 25 30 35 45 50 55 60 65 4 such as an Integrated Services Digital Network ISDN terminal adapter Similarly it should be appreciated that the present invention is not dependent upon the pa
6. the more important aspects of computer operation today that is the ability to communicate with other computers still remains a repetitive and relatively obscure procedure Accordingly it is a principal objective of the present invention to provide a method and system for automatically detecting the data communication settings being used by another computer and automatically configuring the data communication settings to this computer without necessar ily having any advance knowledge of the computer other than a telephone number or interface address It is another objective of the present invention to provide an auto detect method and system which is capable of detecting both the transmission word format and the termi nal standard being employed without requiring any user intervention or pre arranged communication protocol or handshaking procedure It is a further objective of the present invention to provide an auto detect method and system which is independent of the data being transmitted or the specific modem sets or interfaces being employed It is an additional objective of the present invention to provide an auto detect method and system which is capable of turning itself off as well as checking for line noise and reinitialization requests SUMMARY OF THE INVENTION To achieve the foregoing objectives the present invention provides a method and system which is adapted to receive a data stream and test a series of multiple
7. Yes then the AD701 member of the data structure will be incremented by one block 320 The third test is to see if the most significant bit of the character is a binary 1 diamond 316 If the answer is Yes then the ADHighBits member of the data structure will be incre mented by one block 322 Once these three tests have been conducted then a check will be made to see if all of the data words read from the communication port have been processed diamond 324 Assuming that the answer is No then the Auto Detect Analyze method 214 will return to block 310 in order to obtain the next data word The results of these three tests on the example of using the English word Hello followed by the Enter key are shown in Tables 3A 3C for each of the identified word formats For example in the case of the 701 word format the answer to the first test is No for each letter in the English word Hello and Yes for the Enter key Accordingly the value of ADMix is 0 until the Enter key is processed in which case ADMix contains the value of 1 In contrast the answer to the second test is Yes for letter in the English word Hello as well as for the Enter key Accordingly the value of AD701 increments by 1 as each of these data words are processed TABLE 3A 701 Example Enter o 1 1 e H 1 yes 0 no 0 no 0 no 0 0 no Mix 6 yes S yes 4 yes 3 yes 2 yes 1 1701 5 5 4 y
8. bit sequences from this data stream against a plurality of different character forming criteria until both of the following events have occurred Specifically a predetermined number of the mul tiple bit sequences must be received and tested and a predetermined mix of multiple bit sequences satisfying at least two of the character forming criteria must be received and tested Once both of these events have occurred then a data word format is determined from the results of this testing and the computer is configured to interpret charac ters from the data stream in accordance with this data word format setting The present invention is also adapted to test the characters interpreted from the data stream against a plurality of 5 553 271 3 terminal emulation criteria until a character sequence has been detected which is indicative of only one terminal emulation standard In this regard a multiple level state machine is advantageously employed to facilitate a rapid and reliable determination of the emulation mode that should be employed for the current communication session Additional features and advantages of the present inven tion will become more fully apparent from a reading of the detailed description of the preferred embodiment and the accompanying drawings in which BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 is a diagrammatic representation of the auto detect data communication system according to the present inven tion
9. has been read and tested c after conditions exercising both first and second word formats have occurred and after a predetermined num ber of units has been read and tested determining the stream to be one of said word formats as follows d determining the data stream to be of the third word format if said first and second word formats were recorded as not satisfied in step a e determining the data stream to be of the first word format if only said second word format was recorded as not satisfied in step a f determining the stream to be of the second word format if only said first word format was recorded as not satisfied in step a 11 The invention according to claim 3 wherein said third processing means determines a data word format setting from the results of said testing step by a reading a unit from the data stream and testing a most significant bit against remaining bits to determine which of the first and second word formats is not satisfied by the unit and storing data recording that the word format was not satisfied by the unit b repeating step a for successive units until conditions exercising both first and second word formats have occurred and until a predetermined number of units has been read and tested c after conditions exercising both first and second word formats have occurred and after a predetermined num ber of units has been read and tested determining the stream to be one of sai
10. having odd parity using all eight bits of the data word ADHighBits for the number of data words having the high bit set FramingErrors for the number of framing errors encountered ADRunning a flag indicative of whether the Auto Detect method is currently enabled ADLastChar a flag indicative of whether the same character is being transmitted again ADToggleParity a flag indicative of which way to toggle the parity bit ADReconfigure a flag indicative of there being enough data to make a word format determination ADBestGuess a value indicative of which word format has been selected on an interim basis for output transmissions Once the Auto Detect Analyze method 214 has been initial ized a check will be made for the presence of any framing errors diamond 304 A flaming error in this context rep resents a failure to detect the stop bit Accordingly the existence of flaming errors may indicate that the wrong baud rate has been set or that an unusual communication setting has been encountered In any event it would not be effective to continue the Auto Detect Analyze method 214 until the flaming error condition is corrected Accordingly the Auto Detect Analyze method 214 will be stopped blocked 306 While a visual indication of the problem could be sent to the user s display screen an effort to automatically correct the problem and resume the Auto Detect Analyze method 214 could also be developed Assuming that there are no fr
11. of a plurality of 5 computer terminal types without requiring any advance knowledge of the communication settings used to transmit data or the information contained in said data comprising the steps of receiving a data stream by said computer interpreting the presence of characters from multiple bit sequences in said data stream processing combinations of said interpreted characters through a state machine having a plurality of different table levels that progress toward the identification of a unique emulation mode causing said computer to execute combinations of said interpreted characters which satisfy one of a plurality of emulation modes that satisfy said combinations until a unique emulation mode has been determined determining a unique emulation mode from the results of said processing step and causing said computer to lock in said determined emula tion mode 10 The invention according to claim 1 wherein step of determining a data word format setting from the results of said testing step includes a reading a unit from the data stream and testing a most significant bit against remaining bits to determine which of the first and second word formats is not satisfied by the unit and storing data recording that the word format was not satisfied by the unit b repeating step a for successive units until conditions exercising both first and second word formats have occurred and until a predetermined number of units
12. received as hex codes 0x0D and 0x0A The 0x0D is legal as an 8n1 character or as 701 character but not a 7e1 character Similarly the 0x0A is legal as 8 1 character or as a 7el character but not a 701 character Turning now to FIG 3E a flow chart is shown which illustrates the Auto Detect Output method 356 according to the present invention This method takes advantage of the interim determination made in FIG 3D to send data to the transmitting computer 12 As in the case of the Auto Detect Analzye method 214 the Auto Detect Output method 356 begins with a check to see if the Auto Detect method is already running diamond 358 Assuming that the answer is YES then a decision will be made as to which word format should be used to send data to the transmitting computer 12 based upon the value of the ADBestGuess value decision block 360 As illustrated in FIG 3E a switch case state ment combination is preferably employed However it should be understood that other suitable processing tech niques also may be employed In the case that the ADBestGuess value has been set to AD 8NI1 block 362 then no action has to taken other than to pass the data to the communication port as the data has already been treated as being in the 8nl word format 5 553 271 13 However in the case that ADBestGuess value has been set to AD 7 1 block 366 then the data words will be converted to the 7e1 format block 368 Similarly in th
13. which is commonly used to store text Letters numbers and special characters and so forth are represented by different sequences of binary 1 s and 0 s which consist of seven data bits per character While the use of seven bits per character permits a total of 128 different characters there is an extended ASCII character set which is used for graphics and other special characters The extended ASCII character set is based upon eight bits per character and it enables another 128 different characters to be represented in code for a total of 256 possible characters The 8n1 word format is based upon the extended ASCII character set while the other two word formats are based upon the seven bits per character ASCII character set In light of the fact that an asynchronous transmission protocol is used with the 8n1 701 and 7e1 word formats the word format itself must contain the information necessary to apprise another computer entity as to where the code begins and ends Accordingly each of these three word formats include a start bit and a stop bit By convention the start bit 5 553 271 7 is always binary 0 and the stop bit is always binary 1 In the 8n1 example the word format consists of the start bit the extended ASCII code and the stop bit as shown in Table 1 In contrast the other two word formats include the provision of a parity bit which is interposed between the stop bit and the most significant bit
14. 111011000 1011011000 1011011000 1111001010 1011001010 1011001010 1110010000 701 1010010000 7el 1010010000 8 1 From an examination of Table 2 it should be appreciated that there can be many instances when the data words are identical even though two different word formats are being employed For example the data words for the English word Hello are the same for both the 7e1 and 8n1 word formats Accordingly if the data words for Hello were transmitted the receiving computer 14 would have a rather difficult time discerning which data word format was being used Simi larly the data word for the Enter key is the same for both the 701 and 8 1 word formats In light of the fact that the 701 Setting Example Odd Parity Bit Most Sign 6th 5th 4th 3rd Bit Bit Bit Bit Bit 2nd Bit Stop Character Bit Least Sign Bit Start Bit 0 1 1 1 1 1 1 1 e eee orm 1 1 1 1 1 co Tel Setting Example Most Sign 6th Sth 4th 3rd Bit Bit Bit Bit Bit Even Parity Bit 2nd Bit Stop Character Bit Least Sign Bit Start Bit 1 1 1 1 1 1 Ore eee ooooooc Pee o oooo 8 1 Setting Example Most Sign Bit 6th Sth 4th 3rd Bit Bit Bit Bit Bit 2nd Bit Stop Character Bit cooocoo Omen
15. 202 is No then the Receive Refill routine 202 will proceed directly to reading the communication port block 206 In this case the computer 14 will employ the communication settings which have either been set manually by the user or set automatically as a result of the present invention Next the Receive Refill routine will check for the pres ence of communication errors diamond 208 In one form of the present invention the Read Comm block 206 is a function which will return a value based upon whether or not the reading procedure was successful If hardware or soft ware problems outside of the scope of this invention prevent one or more characters from being read accurately from the data stream then the Receive Refill routine will respond by recording the error and removing the data word character from further processing block 210 In one form of the present invention the various routines of the auto detect communication method could be constructed in the C programming language and compiled for the Microsoft Windows environment In such a case certain functions available in the Microsoft Windows API may be employed such as ReadComm for reading a pre specified number of characters from a prespecified communication port and copying these characters into a pre specified buffer and GetCommError for specifying the error code returned from the ReadCorem function However it should be appre ciated that other suitable functi
16. U S Patent Sep 3 1996 Sheet 6 of 7 5 553 271 BEGIN 356 AUTO DETECT OUTPUT NO IS AUTO DETECT ALREADY RUNNING START AUTO DETECT AND INITIALIZE ALL COUNTERS TO ZERO 358 360 YES SWITCH DECISION BASED UPON VALUE OF nADBESTGUESS 374 366 CASE CASE CASE CASE AD_8N1 AD_7E1 AD_701 AD_DONT_KNOW CONVERT CHARACTERS TO 7 1 CONVERT CHARACTERS TO 7 1 ALTERNATELY TOGGLE PARITY BIT PASS DATA TO COMM PORT SELECTED 364 Fig 3E U S Patent Sep 3 1996 Sheet 7 of 7 5 553 271 216 BEGIN TERMINAL ANALYZE YES 400 IS THE EMULATOR LOCKED IN 404 IS THIS AN ANSI ONLY SEQUENCE YES ANOTHER UNIQUE EMULATOR SEQUENCE THRESHOLD LOCK INTO ANSI LOCK IN EMULATOR TYPE DETECTED PROCESS COMMAND CONTROL CODE 408 Fig 4 5 553 271 1 AUTO DETECT SYSTEM AND METHOD FOR DATA COMMUNICATION BACKGROUND OF THE INVENTION The present invention generally relates to data commu nication and particularly to a system and method for auto matically detecting and responding to the transmission set tings used by a data communication transmitter More specifically the present invention is designed to automati cally configure both the word format interpreter as well as automatically select the type of terminal needed to be emulated at the data communication receiver Anyone who has ever spent much time with a computer
17. aming errors then the sample size will be added to the ADTotal value in the data structure block 308 This sample size will be the total number of data words read from the communication port in block 206 of FIG 2 In this regard it should be appreciated that if the Auto Detect Analyze method 214 is still running the next time that the Receive Refill routine 200 is called then the ADTotal value will represent that total number of data words from any and all of the previous instances in the current communication session that the AutoDetect Analyze method 214 has been run including the present instance The next data word will then be obtained from the buffer in memory where the received data words are temporarily being stored block 310 In the first instance block 310 will be used to obtain the first data word which has been read from the communication port of the receiving computer 14 A series of three tests will then be performed on the present 20 25 30 35 45 50 55 60 65 10 data word or character being processed as represented by diamonds 312 316 The first test is to see if there is an odd number of bits in the least significant seven bits of the character diamond 312 If the answer is Yes then the ADMix member of the data structure will be incremented by one block 318 The second test is to see if there is an odd number of bits using all eight bits of the character diamond 314 If the answer is
18. comprehensive high performance communication program such as HyperAC CESS for Windows or 85 5 for DOS or OS 28 Each of these exemplary communication software products are commercially available from the Hilgraeve Inc Monroe Mich While the present invention may be implemented in part through software it should be understood that a hardware only implementation may also be provided in the appropriate application For example a set of interconnected logic gates could be provided to filter desired information from the data stream being received and counters provided to increment or otherwise record the 5 553 271 5 results of the filtering action An additional set of logic gates or a set of comparators could then be employed to make the communication setting determinations after a sufficient number of signals from the data stream have been tested to produce a reliable determination as will be more fully described below FIG 2 shows that the auto detect communication method may advantageously form part of a Receive Refill routine 200 which is in turn part of a larger communication program The Receive Refill routine is called when the buffer used to receive data is empty in order to refill it This routine assumes that data is being received and it needs to be processed In other words for example a communication session has been initiated between computers 12 14 and the receiving computer 14 must no
19. d word formats as follows 10 15 25 30 35 45 50 60 65 5 553 271 17 18 d determining the data stream to be of the third word f determining the stream to be of the second word format format if said first and second word formats were if only said first word format was recorded as not recorded as not satisfied in step a e determining the data stream to be of the first word format if only said second word format was recorded 5 not satisfied in step a satisfied in step a
20. e case that ADBestGuess value has been set to AD 701 block 370 then the data words will be converted to the 701 format block 372 In contrast in the case that ADBestGuess value is still at its default value AD DONT _ KNOW block 374 then the parity bit will be toggled every other time as long as the same single character is being sent to the transmitting computer 12 This is done to give the best possible chance of responding to the transmitting computer 12 with data that it expects Referring to FIG 4 a flow chart which illustrates the Terminal Analyze method 216 is shown This method relies upon the use of a state machine to determine the type of terminal mode being used by the transmitting computer 12 In one form of the present invention each terminal emulator is provided with its own state table A small portion of the one of the tables employed in the state machine is set forth below H State 0 10 0 01 0 01 nothing 0 TEST 5 OxFF std graphic 11 ESC ESC nothing 0 TEXT TEXT tabn 10 TEXT r carriage return I State 1 12 TEXT TEXT ANSI_Pn_Clr 10 TEXT D TEXT D ANSI IND 10 ANSI NEL 10 TEXT H TEXT H ANSL_HTS 12 TEXT Y emuAutoNothing VT52 VT52 Terminal sequence detected 13 TEXT 8 TEXT 8 emnuAutoSaveCursorVT100 VT100 Terminal sequence detected State 2 10 TEXT P TEXT p5 em
21. es 3 yes 2 yes 1 yes TABLE 3B Jel Example Enter o 1 1 l yes 0 0 no 0 no 0 no 0 no mix 0 no 0 no 0 no 0 no 0 no 0 Tol l yes 0 0 no 0 no 0 no 0 no HB TABLE 3C 8 1 Example Enter o 1 1 e H 1 yes 0 no 0 0 no 0 no 0 no Mix l yes 0 0 no 0 no 0 no 0 no 701 0 no 0 no 0 no 0 no 0 no 0 no HB The next step in the Auto Detect Analyze method 214 is to determine if enough data words have been received and the mix between even odd numbers of bits is such that the type of data word format being used may be reliably detected diamond 326 In this regard it should be appre ciated from the discussion of Table 2 that many data words may qualify as legitimate data words under more than one format Accordingly a sufficient number of data words need to be processed in order to achieve high probability of 5 553 271 11 successfully detecting the data word format being used However the mere number of data words processed is in and of itself not a reliable indicator because a string of data words could conceivably all have the same potential parity Accordingly a mix of even and odd parity candidates is needed in order to be sure that an accurate determination can be made without operator interaction In one form of the present invention the number of data words processed is preferably on the order of 15 to 20 and the mix between odd even pa
22. ewing information from the host computer The technique of simulating the 20 25 30 45 50 55 60 65 2 operation of a computer terminal is called terminal emula tion and it is needed in order to convey non text character codes between computers For example screen codes are needed in order to properly display text and graphics such as wrapping text onto the next line of the monitor or screen when the line of text would otherwise extend beyond the fight edge of the screen Control codes are also used to execute a command such as break to interrupt commu nication between the computers There are various types of terminal standards currently in use such as ANSI VT100 TTY and IBM3278 and each of these terminals have their own complete set of key code meanings and display sequences Unless all of this information has already been pro grammed into a computer it will be up to the computer user to intelligently enter this information into his her computer for each telephone number or computer system that the user needs or desires to conduct a communication session In light of the fact that there is a multitude of commercial vendor support and private bulletin board services available to a computer user today the user may have to repeat the process of configuring the communication settings quite a number of times without really having a reasonable under standing of the underlying process In other words one of
23. f the least understood aspects of using a computer For example while most people have a general understanding that baud rate is somehow a measure of communication speed relatively few people fully appreciate what this measurement means or realize that the effective baud rate can be considerably different than the rating of the modem itself Additionally the user is usually confronted with determining several interrelated settings for interpreting a computer word which are less than intuitive such as parity the number of data bits and the number of stop bits For example the parity setting could be configured with one of the following choices none even odd mark or space In contrast the number of data bits could alternatively be configured with numbers such as 8 7 6 or 5 depending upon the choice made for the parity setting Likewise the number of stop bits could alteratively be configured with numbers such as 1 1 5 or 2 depending upon the choices already made for the other two settings Furthermore computers generally communicate with each other as though they were a specific type of standard terminal that would be connected to a particular host computer even though only the smallest of micro computers are involved in the communication Generally speaking a computer terminal includes at a minimum a keyboard for entering information from the host computer and a display such as a CRT cathode ray tube for vi
24. hat the answers to both diamonds 344 346 are NO then the ADBestGuess value in the data structure will be set to 8NI which is an integer value representing the 8n1 word format block 352 Prior to the time that blocks 348 352 are employed to set the value for ADBestGuess the value for ADBestGuess is set t AD DONT KNOW which is a neutral default value This possible value for ADBestGuess is represented by block 354 From the above it should be appreciated that the 7e1 word format may be ruled out by any character with an odd number of binary one bits Similarly the 701 word format may be ruled out by any character with an even number of binary one bits In contrast the 8n1 word format is not ruled out until a final determination can be made As soon as the first data word is received it is possible to rule out either the 701 or 7 1 word formats As long as the data has not proved to be the 8hi word format it is ambiguously the 8n1 word format or one of the 7 bit combinations However it is possible to eliminate both of the 7 bit combinations in as few as two data words For example with a carriage return character CR and a line feed character LF it is possible to determine if either of the 7 bit combinations are being used This is because each of these two characters effectively rules out one of the three choices leaving only the 8n1 word format Using the CR LF example it may be assumed that the following two data words are
25. it significance second processing means for testing a series of multiple bit sequences from said data stream against said first second and third defined word formats until a prede termined number of said multiple bit sequences have been received and tested and a predetermined mix of multiple bit sequences satisfying at least two of said defined word formats have been received and tested third processing means for determining a data word format setting from the results of said second process ing means and storage means for configuring said computer to interpret said data stream in accordance with said data word format setting 4 The invention according to claim 3 further including fourth processing means for testing characters interpreted from said data stream against a plurality of terminal emu lation criteria until a character sequence has been detected which is indicative of only one terminal emulation standard 5 The invention according to claim 4 wherein said fourth processing means includes a state machine which includes a plurality of levels for determining when a character sequence has been detected which is indicative of only one terminal emulation standard 6 The invention according to claim 3 wherein said data stream is a serial data stream which has been received from another computer 7 The invention according to claim 6 wherein said interface means includes a modem and a buffer for tempo rarily holding said da
26. knows that installing just about anything new can be both a frustrating and time consuming experience Even when all of the hardware and software is properly installed the addition of a new capability can present yet another chal lenge to the user For example something as simple as calling a new telephone number with a computer is not as easy as it sounds With normal voice telephone communi cation only a telephone number is needed to initiate a telephone call and absolutely nothing is needed to answer an incoming call However this is not the case with com puter to computer telecommunication or other forms of serial communication between computers In order for two computers to communicate effectively each of them must be able to understand the codes that the other is transmitting whether these codes represent text control or screen char acters Even a person s ability to understand a spoken word such as Hello depends upon a knowledge of the English language In other words the mere act of providing a computer with the telephone number of another computer will not guarantee that either computer will be able to understand even a single character of text from the other Rather various disparate communication settings must be properly configured in order for two computers to commu nicate through a modem or other data stream interface Unfortunately the configuration of a computer s commu nication settings is possibly one o
27. ly inter preted characters to the display panel 40 there are a variety of control codes which do not necessarily effect or change what the user sees on the display panel 40 In order to have a better appreciation for how the present invention detects the type of word format being used by the transmitting computer 12 the three most commonly used word formats used for asynchronous serial data communi cation will be discussed first These word formats are referred to herein as 8n1 701 and 7 1 As discussed above 8n1 stands for eight bits per character no parity and one stop bit Similarly 701 stands for seven bits per character odd parity and one stop bit Finally 7 1 stands for seven bits per character even parity and one stop bit From this brief description it should be apparent that all three of these word formats have one stop bit as a common setting However it should also be noted that all three of these formats also employ a total of ten bits per data word These three formats are illustrated in Table 1 below using the example of a simple transmission of the English word Hello to the receiving computer Accordingly Table 1 shows the coding used for each of the letters in the word Hello as well as the coding for the Enter key on the keyboard of the transmitting computer 12 Each of these codes are based upon the American Standard Code for Information Interchange ASCH
28. memory e g RAM or Flash memory to run the computer programs needed by the computer a storage device e g hard disk drive 36 a monitor or flat panel display e g monitor 38 and display panel 40 and a keyboard or other input device e g keyboard 42 Again however it should be understood that the present invention is not limited to any specific set of computer hardware components and that the present invention may be used with a variety of computer entities which are otherwise capable of transmitting and receiving data signals between other com puter entities For example the present invention could be integrated into the operation of a modem as opposed to employing the processing capability of the computers 12 14 In other words the modems 20 22 could be con structed to perform the auto detect methods according to the present invention The modems could then either identify the proper communication settings for their respective comput ers or perform the necessary signal conversions so that the modems always use a predetermined pattern of communi cation settings with their respective computers On the other hand the functionality provided by the modems 20 22 could also be integrated into their respective computers as well Referring to FIG 2 an overall flow chart of the auto detect communication method according to the present invention is shown In this regard it should be pointed out that this method may form part of a
29. mix of multiple bit sequences satisfying at least two of said defined word formats have been received and tested determining a data word format setting from the results of said testing step and configuring said computer to interpret said data stream in accordance with said data word format setting 2 The invention according to claim 1 further including the step of testing characters interpreted from said data stream against a plurality of terminal emulation criteria until a character sequence has been detected which is indicative of only one terminal emulation standard 3 A system for automatically configuring the communi cation settings of a computer to interpret a data stream without requiring any advance knowledge of the word format used to transmit said data stream or the information contained in said data stream comprising interface means for receiving a data stream first processing means for defining a first word format wherein a unit of information is represented by a plurality of bits the most significant bit being a parity bit of a first polarity said first processing means also a second word format wherein a unit of information is represented by a plurality of bits the most significant bit being a parity bit of a second polarity said first processing means also defining a third word format wherein a unit of information is represented by a plurality of bits the most significant bit having no parity b
30. mmm United States Patent ro 1 Patent Number 5 553271 Hile et al 45 Date of Patent Sep 3 1996 54 AUTO DETECT SYSTEM AND METHOD 5 097 528 3 1992 Gursahaney et al 379 67 FOR DATA COMMUNICATION 5 222 081 6 1993 Lewis et al vee 375117 5 274 679 12 1993 Abe et al 375 117 751 Inventors John Hile Monroe Michael R Ward Ann Arbor both of Mich OTHER PUBLICATIONS HyperAccess Communications Software For Windows 73 Assignee Hilgraeve Incorporated Monroe User s Manual Hilgraeve Inc 1993 written and produced Mich by Mahler Associates Inc Ann Arbor Michigan Primary Examiner Kevin J Teska 21 Appl No 273 481 Assistant Examiner Russell W Frejd 22 Filed Jul 11 1994 Attorney Agent or Firm Harness Dickey amp Pierce 51 Int CES u a G06F 9 455 57 ABSTRACT E n S eae re 34071725 4 tee method and system which is adapted to receive a data 58 Field of Search Rr d stream and test a series of multiple bit sequences from this 370 94 235 435 379167 395 500 data stream against a plurality of different character forming 56 References Cited criteria until both of the following events have occurred Specifically a predetermined number of the multiple bit U S PATENT DOCUMENTS sequences must be received and tested and a predetermined mix of multiple bit sequences satisfying at least two of the 3552 ee
31. n this regard it is evident that those skilled in the art once given the benefit of the foregoing disclosure may now make modifications to the specific embodiments described herein without departing from the spirit of the present invention Such modifications are to be considered within the scope of the present invention which is limited solely by the scope and spirit of the appended claims What is claimed is 1 A method of automatically configuring the communi cation settings of a computer to interpret a data stream without requiring any advance knowledge of the word format used to transmit said data stream or the information contained in said data stream comprising the steps of defining a first word format wherein a unit of information is represented by a plurality of bits the most significant bit being a parity bit of a first polarity defining a second word format wherein a unit of infor mation is represented by a plurality of bits the most significant bit being a parity bit of a second polarity defining a third word format wherein a unit of information is represented by a plurality of bits the most significant bit having no parity bit significance receiving said data stream by said computer testing a series of multiple bit sequences from said data stream against said first second and third defined word formats until a predetermined number of said multiple bit sequences have been received and tested and a predetermined
32. o see if the emulator mode has already been locked in diamond 400 If the answer is Yes then the method will proceed immediately to processing the command text or control 10 15 20 30 35 45 50 55 60 65 14 code read from the communication port block 402 Oth erwise the method will proceed into the state machine discussed above In one form of the present invention the state table is preferably constructed to check for an ANSI only sequence first diamond 404 For example many ANSI only sequences begin with the Escape key followed the left square bracket key such as ESC 3 5 m for setting the foreground and background colors of the display If an ANSI only sequence is detected by traversing the state table discussed above then the method will call the function which will lock in the emulation mode detected and execute the control sequence being processed block 408 Other wise the method will continue traversing the state table in order to detect other unique emulation mode sequences diamond 410 Lastly if an emulation mode was not detected a threshold evaluation will be done to check for the number of logins or times that the Terminal Emulation Analyze routine 214 was called diamond 412 If the number of detecting attempts exceeds a predetermined value then the most widely used terminal mode will be locked in as a default The present invention has been described in an illustrative manner I
33. of the seven bit per character ASCII code The parity bit is added by the transmitting computer 12 as a standard technique enabling transmission errors to be detected at the receiving computer 14 The added parity bit Enter 1000011010 1100011010 1000011010 makes the sum of binary one bits in the data word either an odd number for odd parity or an even number for even parity without including the start or stop bits While the present invention is described in connection with examples of using word formats having ten bits per data word it should be appreciated that the present invention could be suitably modified to detect communication settings which employ a greater or lesser number of bits per char acter Similarly the present invention is not limited to the use of ASCII coding in order to perform its detection functions and other suitable coding techniques could be used in the appropriate application TABLE 1 1111011110 1011011110 1011011110 20 8 In a serial transmission scheme the data words are transmitted sequentially as illustrated in Table 2 Table 2 illustrates how each of the data words would be transmitted under each of the word formats described above In this regard it should be pointed out that there are not necessarily spaces or pauses between data words when they are being transmitted TABLE 2 Example of Alternate Serial Transmission Parameters o 1 1 1111011000 1011011000 1011011000 1
34. ons and operating environ ments could be utilized in the appropriate application 30 35 40 45 50 55 65 6 Assuming that no communication errors were encoun tered then the Receive Refill routine will check to see if the Auto Detect feature is still turned on and the carrier is connected diamond 212 If the answer is Yes then the Receive Refill routine will call the Auto Detect Analyze routine 214 in accordance with the present invention If the answer is No then the Receive Refill routine will proceed to the Terminal Emulation Analyze routine 216 The Auto Detect Analyze routine 214 is designed to detect the type of data word format being used by the transmitting computer 12 for character coding and configure the communication port to this format Similarly the Terminal Emulation Ana lyze routine 216 is designed to detect the type of terminal that the transmitting computer 12 is emulating and to lock in the receiving computer 14 to this type of terminal emu lation Once both the data word format and terminal emu lation settings have been configured then the data read from the communication port is passed on to the emulator portion of the communication program for further processing block 218 For example the emulator software will be responsible for responding to the terminal control codes received from the transmitting computer 12 While this terminal emulation responsibility may be as simple as sending proper
35. or 7 1 word formats are being used Accordingly for purposes of this example the communication parameters will be set to 8n1 block 338 However a check could also be made to see if the ADHigh Bits value was equal to ADTotal In such a case it is possible that the data word format could be a less frequently used format such as 7mark1 and additional tests may be required to include less frequently encountered data word formats Finally the Auto Detect Analyze method 214 will be stopped and the communication port will be configured for the detected data word type block 340 This particular data word type will also be stored as part of the configuration for this computer telephone number or address so that subse quent communication sessions will not need to invoke the Auto Detect Analyze method 214 Referring to FIG 3D an additional portion to the Auto Detect Analyze method 214 is shown In this regard this additional portion is directed to making an interim best guess determination of the word format until sufficient data has been received to make a final determination as shown in FIG 3C The flow chart of FIG 3D may be inserted into the flow chart of FIG 3B between diamonds 324 and 326 when an interim word format decision would be beneficial For example an interim word format decision would be beneficial if a message needs to be sent from the receiving computer 14 to the transmitting computer 12 before a final determina
36. rity candidates is preferably on the order of 8 While diamond 326 is shown to follow diamond 324 in FIG 3B it should be appreciated that the order could readily be reversed depending upon the number of data words already processed Similarly the order of the tests described above could readily be changed and further tests could be added in order to handle other possible data word types In the event that the answer to diamond 326 is No then the most significant bit of all of the data words will be set to zero in order to turn any graphic characters into text to minimize potential confusion to the user block 328 Once both conditions of diamond 326 have been satisfied then the Auto Detect Analyze method 214 will proceed to determining the data word format used by the transmitting computer 12 Using the three data word formats discussed above as an example the data word format may be deter mined from an analysis of just the AD7o1 and ADTotal member values Specifically if the value of AD701 is equal to zero diamond 330 then this means that the 7 1 format is most probably being used and the communication param eters will be set to 7 1 block 332 Similarly if the value of AD701 is equal to ADTotal diamond 334 then this means that the 701 format is most probably being used and the communication parameters will be set to 701 block 334 If the answer to both of the diamonds 330 and 334 is No then this means that neither the 7o1
37. rticular trans mission medium being employed for the communication session Accordingly the medium of communication is generically illustrated in FIG 1 between the various devices such as the communication line 26 between the modem 20 and the switching station 16 These communi cation lines 24 32 may be used to represent any suitable communication medium such as copper wire fiber optic cable radio waves and so forth FIG 1 also shows a second form of data communication namely data communication which is more directly between the transmitting computer 12 and the receiving computer 14 In this case the computers 12 14 could be connected together over a local area network or to each other s serial communication ports To illustrate these types of connec tions FIG 1 includes a communication line 34 between the transmitting computer 12 and the receiving computer 14 However in a multiple CPU or multiple threaded process ing environment it should be understood that the transmit ting computer 12 and the receiving computer 14 could also be part of the same physical computer entity In any event the transmitting computer 12 and the receiv ing computer 14 should include the hardware components which are typically included in commercially available computer systems or work stations For example the com puters 12 14 should both be equipped with a mother board having a CPU Central Processing Unit and sufficient randomly accessible
38. ta stream until all of said testing has been completed 8 A method of automatically configuring the communi cation settings of a computer to interpret a data stream without requiring any advance knowledge of the word format used to transmit said data stream or the information contained in said data stream comprising the steps of receiving said data stream by said computer defining a first word format wherein a unit of information is represented by a plurality of bits the most significant bit being a parity bit of a first polarity defining a second word format wherein a unit of infor mation is represented by a plurality of bits the most significant bit being a parity bit of a second polarity defining a third word format wherein a unit of information is represented by a plurality of bits the most significant bit having no parity bit significance testing a series of multiple bit sequences form said data stream against at least one of said first second and third defined word formats determining at least an interim data word format setting from the results of said testing step after at least two multiple bit sequences have been received which have potential for meeting two of said defined word formats and 3 553 271 16 causing said computer to transmit data streams in accor dance with said interim data word format setting 9 A method of automatically configuring the communi cation settings of a computer to emulate one
39. tion has been made as will be described in con nection with FIG 3E The key to being able to make an interim decision occurs when at least two data words have been received with different potential parity settings This is illustrated by diamond 342 which determines if ADMix is greater than zero and less than ADTotal Under these conditions at least one data word has been received with the 20 30 35 45 50 55 65 12 potential for even parity and at least data word been received with the potential for odd parity As soon as there are candidate characters for both even and odd parity a tentative word format decision is imme diately possible This decision making process is illustrated by diamonds 344 and 346 Specifically diamond 344 checks to see if the number of data words received with odd parity potential is equal to the total number of data words received then means that the 701 format is most probably being used Accordingly the ADBestGuess value in the data structure will be set to AD 701 which is an integer value represent ing the 701 word format block 348 Similarly diamond 346 checks to see if the number of data words received with odd parity potential is equal to zero then means that the 7 1 format is most probably being used Accordingly the ADBestGuess value in the data structure will be set to AD_7E1 which is an integer value representing the 7 1 word format block 350 In the event t
40. uAutoNothingAnsi 10 TEXT s TEXT 5 emuAutoSaveCurAnsi 10 TEXT q emuAutoNothingVT100 15 TEXT ANSI_PN H State 3 3 0x00 OxFF emuStdChkZmdm if State 4 4 0x00 OxFF nothing State 5 10 2 TEXT 2 emuAutoPnAnsi 10 TEXT 5 TEXT 5 emuAutoPnAnsi 0 TEXT p TEXT p emuAutoNothing VT100 The first field in this state table indicates the next state in the table to examine Accordingly a 0 in this field means that the machine should stay in the lowest or 0 state while a 3 in this field means that the machine should proceed to the third state The next two fields in the table indicate the range of characters that may be matched in terms of their character or ASCII code value The last field in the table identifies a function that should be called For example the field value emuAutoNothingVT52 means that a VT52 terminal con trol sequence has been detected and function being called will enable the VT52 emulation mode to be locked in and the control sequence to be executed In contrast the field value ANSI IND means that a sequence has been detected which is common to both an ANSI terminal and one or more other types of terminal modes However the function being called will execute the sequence as though it were an ANSI terminal Turning now specifically to FIG 4 the first step of the Terminal Emulation Analyze method 216 is a check t
41. w interpret the information being conveyed in the data stream sent by the transmitting computer 12 This communication session could be initiated by the receiving computer 14 once the user has entered the telephone number or interface address into the communi cation program responsible for handling this communication session In order to minimize the interaction of the user with the initial setup procedure for the communication session the communication program could be programmed to use the baud rate negotiated by the modem 22 and always turn on the Auto Detect feature as hereinafter described in detail The first step in the Receive Refill routine 200 is to check if the Auto Detect feature is currently turned on or otherwise enabled diamond 202 If the answer is Yes then the communication port of the receiving computer 14 will employ a predetermined word format which preferably is a word format which does not lose any data if it is incorrect block 204 In this regard the currently preferred word format is 8n1 which stands for eight bits per character no parity and one stop bit In other words the communication port will be configured to interpret the initial data received in a way which provides the highest probability of being correct In this regard it should be understood that there is no parity bit in this word format which could be stripped off as not being part of the data sequence In the event that the answer to diamond
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