Multiplexer User's Guide
Contents
1. Figure 3 Data link layer OxF9 Mux_guide_ v05 Page 17 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 4 2 1 Flag sequence A flag sequence is a specific bit pattern usually 11111001 hexadecimal OxF9 used to mark the beginning and the end of a frame of data Each frame begins and ends with a flag sequence Only one flag sequence occurs between any two frames If two successive flag sequences do occur the frame is regarded as being empty and is discarded The flag sequence is used for the synchronization of frames 4 2 2 Address field Data link connection identifier is a frame relay term defining a 10 bit field of the address field The DLCI identifies the data link and its service parameters including the frame size The values for the Data Link Connection Identifier DLCI are dynamically defined apart from DLCI 0 Table 2 Address field EA C R DLCI DLCI Data Link Connection Identifier C R Command Response EA extension bit EA 1 Table 3 Assignment of the DLCI Multiplexer control channel see chapter 5 1 6 pas _ priority The command response bit identifies the frame as a command or response A command contains the address of the data link connection to which the command is sent A response contains the address of the data link connection sending the frame Mux_guide_ v05 Page 18 of 37 17 12 2003 Multiplexer User s Guide SI EM EN2. distribute it on the three virtual channels The external multiplexer needs to be provided by the customer This document describes how to use the multiplexer and then explains how to design an external multiplexer and integrate it into an application on top of a Siemens GSM engine Multiplexer protocol sources WinMux2k provided by Siemens AG can be obtained on request from your local distributor For more detailed information please refer to 5 Mux_guide_ v05 Page 6 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 1 1 Supported products and related documents Supported products AC43 AC45 MC35i MC35i Terminal MC39i MC45 MC46 MC388 MC5x TC35i TC35i Terminal TC45 Related documents 1 Hardware Interface Description supplied with your GSM engine 2 AT Command Set supplied with your GSM engine 3 Release Notes supplied with your GSM engine 4 Remote SAT User s Guide 5 Multiplexer Driver Developer s Guide for Windows 2000 and Windows XP 6 Multiplexer Driver Installation Guide for Windows 2000 and Windows XP For further documents regarding your GSM engine please refer to the latest Release Notes supplied with the module Prior to using your GSM engine be sure to carefully read the latest product information provided in the Release Notes To visit the Siemens Website you can use the following link http www siemens com wm 1 2 References 1 Digital Cellular
3. DIS CONNECTED DLC Establishment Information Transfer Mux_guide_v05 Information Transfer Figure 4 Relationship between the customer uC and the GSM engine uC Page 22 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile Serial interface Customer GSM engine uC T ih Closed Down RequestStartUp gt IndicationStartUp gt lt ResponseStartUp ConfirmStartUp Disconnected Disconnected ReguestSABM gt al IndicationSABM gt lt ResponseDIM _ ConfirmDM Disconnected Disconnected RequestSABM gt Di IndicationSABM gt lt ResponseUA Mm ConfirmUA a 2S co pe lt D D Es i io one SO y amp LU oO ag E oo Eo QS 25 TO W oA e gt f Connected Connected RequestUIH gt a Indication JIH gt Connected Connected Information Transfer lt RequestUIH ndicationUlIH Connected Connected Figure 5 MPI Startup DLC establishment and information transfer Mux_guide_v05 Page 23 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile Serial interface Customer uC GSM engine uC RequestDISC gt IndicationDISC gt lt ResponseUA mM ConfirmUA DLC Release
4. Disconnected Disconnected Disconnected Disconnected Negotiation Negotiation Connected Connected Request equestCloseDown gt IndicationCloseDown gt lt ResponseCloseDown Close Down ConfirmCloseDow1 Figure 6 MP DLC release and close down Mux_guide_v05 Page 24 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 5 1 1 Start up procedure The only approach to activate the multiplexer protocol is entering the appropriate AT command AT CMUX 0 This enables the multiplexer control channel Please keep in mind that as the next step the multiplexer control channel must be set up see Chapter 5 1 2 5 1 2 DLC establishment The multiplexer control channel must be set up as the first channel followed by all other DLCIs To do so a SABM frame see Chapter 4 2 3 must be sent to the GSM engine The module responds with either a UA frame i e the DLCI was set up or with a DM frame if the DLCI was not set up No provision is made for repeating the request if a response is not received The state machine requesting the multiplexer control channel DLCI 0 is the initiating station while the other is called the responding station SABM P 1 Address Field DLCI of channel to be established ee GSM Customer uC engine UA F 1 DLCI is being established DM F 1 not ready DLCI is not established Address Field DLCI o
5. STOP information data sending disabled sent by the module to control the data transmission from the customer application to the module If RTS is reset a STOP is transmitted to the module to control the data transmission from the module to the customer application Figure 2 illustrates the data flow COM M bo Controller COMN RTS CTS maps RTS CTS of the unframed CSD RTS CTS channels to log FC Channel 1 RTS CTS COM P seine P ser Multiplexer rotocol IO io TI Protocol GSM 07 10 GSM 07 10 Channel 2 3 RTS CTS TE AT Customer application MS morace WinMux2k Module HW flow control logical flow control FC Flow control between the applications Figure 2 Logical flow control and RTS CTS signaling behind the decoder RING DCD Contrarily to all other lines DCD and RING are transmitted additionally on the UART directly by the module These signals are logical ORs from the three logical channel status lines However the customer application must carefully decide how to handle these lines and ensure that no conflicts occur between the different channels E g in some situations it may be advisable to display RING on channel 1 only Please keep in mind that a call can only be accepted once Therefore some kind of mutual locking mechanism must be used Mux_gui
6. Telecommunications Systems Phase 2 Terminal Equipment to Mobile Station TE MS Multiplexer Protocol ETSI TS 101 369 V7 1 0 1999 11 GSM 07 10 Version 7 1 0 Release 199 Mux_guide_ v05 Page 7 of 37 17 12 2003 Multiplexer User s Guide Confidential Released 1 3 Term and abbreviations Abbreviation CSD CTS DCD DLCI DSB DSR DTR FC FFC GPRS GSM IEI IP MO MP MS MSDN MT MUX OS PC PSC RTS TE UART Mux_guide_ v05 Description Circuit Switched Data Clear to Send Data Carrier Detect Data Link Control Identifier Developer Support Box Data Set Ready Data Terminal Ready Flow Control Flat Flex Cable General Packet Radio Service Global System of Mobile Communication Information Element Identifier Internet Protocol Mobile originated Multiplexer Protocol Mobile Station Microsoft Developer Network Mobile terminated Multiplexer Operating System Personal Computer Power saving control Request to Send Terminal Equipment Universal Asynchronous Receiver Transmitter Page 8 of 37 SIEMENS Mobile 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 2 Multiplexer protocol an overview 2 1 Product concept and architecture The multiplexer mode enables one serial interface to transmit data to three different custo mer applications This is achieved by providing three virtual channels using a multiplexer Mux This is especially advantageous when
7. frames have a start and a stop byte A checksum is calculated to protect the transferred data Frame repetition is not enabled Data and fax calls are transferred in the logical channel DLCI 1 DLCI Data Link Connection Identifier The remaining DLCIs are in AT command mode two GPRS connections can be established simultaneously on every channel The multiplexer protocol must be started and the logical channels opened in compliance with specified procedures The chapter also gives you suggestions for the following aspects e Opening logical channels without parameter negotiation e Opening logical channels with parameter negotiation e Closing of logical channels a 4 2 Data link layer 1 Octet 1 Octet 1 Octet 1 or 2 Octets n Octets 1 Octet 1 Octet The following sub chapters show the detailed structure of a data link OxF9 frame Checksum for address control and length fields also for the information field in the case of UI frames FCS EA Length Length Length Information EA extension bit EA 1 gt 1 octet length information EA 0 gt gt 2 octets length information Frame type SABM Set Asynchronous Balanced Mode UA Unnumbered Acknowledgement DM Disconnected Mode DISC Disconnect UIH Unnumbered Information with Header check Ul Unnumbered Information P F Bit Poll Final Bit EA C R DLCI DLCI Data Link Connection Identifier C R Command Response EA extension bit EA 1
8. of combinations for version check The TE and MS multiplexer version numbers can be traced on the serial interface They appear as follows e TE version e g version 1 TEMUXVERSION0001 e MS version e g version 2 msmuxvERSIONO002 As already mentioned before the valid multiplexer version is negotiated during the initialization process If TE and MS do not include the same version the lower version will be used Mux_guide_ v05 Page 34 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile Example 1 2 and 3 see Figure 15 This example describes the case if TE and MS support the same multiplexer version without version check Example 4 and 6 Vice versa if the MS does not include version check the TE uses the older protocol version This can be done in various ways e WinMux2k DLLs for all versions are available and have to be chosen according to the negotiated version e Customer application with Siemens AG sources The TE switches back to the older version without version check Since all new protocol features can be used only if they are implemented on the MS side the switch back happens automatically Please ensure that new multiplexer protocol features provided by Siemens AG should be implemented into the MS side of the customer application e Customer application with proprietary multiplexer implementation See Customer application with Siemens AG sources Example 5 and 7 In this ca
9. Chapter 6 More detailed information on older multiplexer versions are available in Chapter 6 2 Break signal optional Bit2 Bits Bit4 Bits Bit Bit7 Bits Usually the break signal octet carries information about a break condition detected from the host application in the data stream for the DLC Note This command supports no parameters Instead we use this optional parameter to transport the escape sequence detection from the host to the module If the customer application detects an escape sequence usually it sends this optional octet with bit 1 set to 1 The module calls its original escape sequence 5 1 6 4 Power saving control PSC The power saving control message uses the following type field octet Type Biti Bit2 Bit3 Bit4 Bits Bit Bit7 Bits 4 eR Jo Jo Jo Jo 1 0 Figure 12 Power Saving Control PSC C R bit Indicates whether the sequence is a command or a response Length The length byte contains the value O no value octet or 1 one value octet Value octet Length 1 Bis Bta ets ene en7 ers P4 oo P2 C PSCC _ Jo _ Jo OT The P bits are defining the parameter value Mux_guide_v05 Page 29 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile In commands Bit4 _ Bit2 _ Bit3 _ Bit4 Description ___ o p p p perre value octet o p p p parrer AT CFUN 1 i N A A e like AT CFUN 0 PP areas COPS RS AT CFUN 5 1 Switches
10. LCI V 24 signals Break Signals optional 1 octet 1 octet 1 octet 1 octet 1 octet Command Figure 11 Modem status command MSC C R bit Indicates whether the sequence is a command or a response Length Length 2 EA Bit 1 V 24 signals FC bit Flow control included in all multiplexer versions FC 1 no frames are accepted The following bits for V24 status lines as described in this chapter are included in multiplexer protocol version 3 only However if you wish to use the advantages of this version it is absolutely necessary to switch on the version 3 otherwise version 1 will be used see Chapter 6 2 Direction host application gt module for request only MUX V3 RTC mapped to DTR RTR mapped to RTS Bit 5 6 7 8 are not valid Direction module gt host application for request only MUX V3 RTC mapped to DSR RTR mapped to CTS RING mapped to RING DCD mapped to DCD Bit 5 6 are not valid Mux_guide_v05 Page 28 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile Note The mappings are valid for version 3 and an MSC request only Descriptions of all other versions are available in Chapter 6 The response to any MSC must be always the same data already sent Please keep in mind that it is impossible to remap any response bits Remember that the bits described above are valid in Mux version 3 only switched on by a version control handshake see
11. Page 36 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 6 3 3 Example of TestCommand message An example for coding a TestCommand message is illustrated in Table 8 Table 8 Coding of TestCommand Example 8 7 6 5 4 3 2 1 0x START Flag Address Field DLCI 0 C R 0 EA 0 Control Field UIH Frame P F 0 Length LENGTH 18 EA 1 Type Field TestCommand C R 1 EA 1 Length Length 16 EA 1 TEMUX VERSION T E M U X V E R S I O N Mux_guide_v05 Page 37 of 37 17 12 2003
12. S Confidential Released Mobile Table 4 Use of the command response bit Command Customer C GSM engine Response Customer C GSM engine o Every command expects a response No provision is made to repeat the command if no response is received 4 2 3 Control field The control field contains control information to define the frame Table 5 Coding of the control field 2p ppe ep p SABM set asynchronous balanced mode UA unnumbered knoe P F Sp DISC P F oom PP unnumbered information with header check P F Poll Final bit Commands P 1 Responses F 1 For each DLCI only one frame with P 1 may ever be expected Mux_guide_ v05 Page 19 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 4 2 4 Length indicator The length indicator specifies the length of the following information field The default length is 31 bytes but can be extended with the E A bit 1st octet Bit4 Bit2 Bits Bit4 Bits Bit Bit7 Bits E A 2nd octet Bit1 Bit2 Bits Bit4 Bits Bit Bit7 Bits E A 1 only one octet for the Length Indicator E A 0 two octets for the Length Indicator 4 2 5 Information field The information field contains the data and has an octet structure The field only exists for UIH frames unnumbered information with header check To transfer information fields the P F bit is set to 0 a response is not necessarily expect
13. SIEMENS Mobile User s Guide Multiplexer User s Guide SI EM ENS Confidential Released Mobile Document Name Multiplexer User s Guide Version 05 Date December 17 2003 Docld Mux_guide_v05 Status Confidential Released General notes Product is deemed accepted by Recipient and is provided without interface to Recipients products The documentation and or Product are provided for testing evaluation integration and information purposes The documentation and or Product are provided on an as is basis only and may contain deficiencies or inadequacies The Documentation and or Product are provided without warranty of any kind express or implied To the maximum extent permitted by applicable law Siemens further disclaims all warranties including without limitation any implied warranties of merchantability complete ness fitness for a particular purpose and non infringement of third party rights The entire risk arising out of the use or performance of the Product and documentation remains with Recipient This Product is not intended for use in life Support appliances devices or systems where a malfunction of the product can reasonably be expected to result in personal injury Applications incorporating the described product must be designed to be in accordance with the technical specifications provided in these guidelines Failure to comply with any of the required procedures can result in malfunctions or serious discr
14. a 11 3 1 1 Basic FEQUITEIMEMIS vcnsssnsscsisonarsatnansceansvssseaiesawaaGianesaeinencsasinmnecenwnnesevcen 11 wL RESO aa E E EE 11 3 1 3 Dependencies between multiplexer channels and restrictions of use 12 3 1 4 Functions without channel dependencies cccecceeeeceeceeeeeeeeeeeees 12 kO MMN CONGIONS srecen eae E i E 13 3 1 6 Operation of a second physical serial interface ASC1 if applicable 13 3 2 Multiplexer control and signaling lines cc cceccececceeceeee eee eeeeeeeeseeseeseeeeeees 14 3 2 1 FOWOM Oaa E E E E 14 3 22 ESCAPES SegUCNCe aicicmicvccssnescasnedsanademonsnndesenunedbpenandaasied suceomeddgentdelinecumens 16 Oe POWT SAVING este seagate sasha eran ete E ate testcase oate eas emtpeaeeaeees ee 16 3 4 Bandwidth of logical Channels ccccccccecceececceeeeeeeeeeeeeceeeeeeceeeseeseeseeeeeeseees 16 4 Structure of the multiplexer protocol ccc cceceeeeeeeeeeeneeneeneeeeeeeseesensenseneeneenenees 17 4 1 Introduction of the multiplexer ProtOCol ccc ccc ceceeeceeceeeeeeeeeeeeeeseeseeeeeeeenees 17 Be NaI VAY ON otros eae ete eate et eae teh ede Hod ade eed aca alee ER E AEE EEE 17 4 2 1 FA SOO O EE E E E E E 18 A22 Addes Nelda a a a A AE meesacnas 18 423 COMMON OIG oce NEEE 19 4 2 4 Length IndiCator ccccccccccecceececceeceeceeeceeceeceeceeceecesaeeceeceeseeseeseesaes 20 42o AMON AN OM CIOs facets nadeusteniecasiesgacntedieawueciccnibewleace
15. a fax data GPRS call is ongoing Using the multiplexer features e g controlling the module or using the SMS service can be done via the additional channels without disturbing the data flow access to the second UART is not necessary Furthermore several accesses to the module can be created with the multiplexer This is of great advantage when several independent electronic devices or interfaces are used To access the three virtual interfaces both the GSM engine and the customer application must contain Mux components which communicate over the multiplexer protocol In multiplexer mode AT commands and data are encapsulated into packets Each packet has a channel identification and may vary in length Note All statements regarding GPRS are valid for AC43 AC45 MC45 MC388 MC35i MC39i TC45 MC46 and MC5x only Terminal programs User application GSM engine or internal programs integrated in cus tomer application platform Terminal 1 Channel 1 Data Fax 1 GPRS supported Serial MP Serial Terminal 2 Channel 2 I O I O Data Fax not supported 3 Terminal 3 gt 7 Channel 3 Figure 1 Multiplexer architecture Mux_guide_ v05 Page 9 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobi
16. andwidth and delay time per channel Therefore the customer application should take care that the channels 2 and 3 are not heavily loaded when faxing on channel 1 Example 1 Checking the field strength every 2 seconds does not harm sending an SMS every 10 seconds may lead to problems Example 2 Reading a complete phone book may cause problems if a fax transmission is ongoing at the same time When switching on the module after a firmware update we recommend to wait 5 seconds before entering the first AT command 3 1 6 Operation of a second physical serial interface ASC1 if applicable This chapter applies only to Siemens GSM modules equipped with a second physical serial interface referred to as ASC1 If your product has only one physical serial interface ASCO you can skip this chapter ASC1 is disabled when the multiplexer is enabled on the first serial interface ASCO Yet both ASC1 and the multiplexer channel 2 are using the same parameters and thus the same user defined profile if any As a result a user profile stored on multiplexer channel 2 takes effect on ASC1 after closing the multiplexer and starting up ASC1 Likewise a user profile stored on ASC1 will be loaded on multiplexer channel 2 This may be a problem when ASC1 is not connected but flow control for example AT Q1 or AT Q3 is stored to the user profile on the multiplexer channel 2 In this case flow control takes effect on ASC1 when the multiplexer is sw
17. ary loss of bandwidth on another channel This behavior has no impact on the handshake V 24 lines RTS CTS on the physical channels Hardware flow control AT Q3 is recommended for use with multiplexer For power saving it is indispensable The setting AT Q3 needs to be made before switching on the multiplexer The customer application decodes and encodes the data To prevent loss of data the application must be able process the information about internal flow control MSC regulated by the module Flow control information is transmitted within the data flow and contains messages whether or not the channel is allowed to send See chapter 5 1 6 3 for MSC As of Multiplexer Protocol version 2 the customer application must set RTS in the direction to the module on channel 1 RTS shall not be switched off to prevent loss of data control data cannot be sent in this case If flow control is needed it is recommended to use logical flow control on every channel Mux_guide_ v05 Page 14 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile RTS CTS on the logical channels The customer application needs to regulate the data flow according to the logical flow control The implementation of the WinMux2k is a good example It maps the 3 decoded channels to 3 serial interfaces as well as the logical flow control information FC BIT in MSC message directly on the RTS CTS control lines In this case CTS superposes the
18. de SI EM ENS Confidential Released Mobile Type field Bir enz Jens ona ons one Jorr Joe EA bit Extension bit In the last octet of the sequence the EA bit 1 otherwise 0 If there is only on octet EA bit 1 is set C R bit Indicates whether the sequence is a command or a response T bits Coding of the command type Length field Ben exe ens axa ons oxo Jon one EA bit Extension bit In the last octet of the sequence the EA bit 1 otherwise 0 If there is only one octet EA bit 1 is set L bits Number of value octets the following L1 is the LSB L7 the MSB Multiple commands can be sent in a single frame only 5 1 6 1 Multiplexer close down CLD Type field Bir enz fons are ons one err one o eP bk b b Length byte 0 no value octet 5 1 6 2 Test command Test The test command is intended to test the connection between MS and TE Type field Bir oxe Jens Jena Jens one Jor one o e ekb bh bP b The length byte indicates the number of test bytes sent in the value bytes The responding station should answer with exactly the same bit sequence The test command is used for the version control For more detailed information see Chapter 6 Mux_guide_v05 Page 27 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 5 1 6 3 Modem status command MSC The Modem Status Command is used for software flow control Command Length D
19. de_ v05 Page 15 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 3 2 2 Escape sequence When the multiplexer protocol is active only coded data is transmitted over the UART The coding includes a header and a checksum Therefore the direct parsing of this sequence is not possible An escape might be undetected because the decoded time relations may be disturbed The following transmission path for the ESC signal has been implemented e DTR is transported within the logical channel To terminate a call the normal way of using DTR is available Please keep in mind that the multiplexer cannot transport this signal in real time Please use a certain gap time between signaling with DTR e tis possible to detect the on the customer multiplex application and transport this information via the MSC signal to the module see Chapter 5 1 6 3 e As an alternative ATH may be sent on one of the other channels for more detailed information please refer to 2 3 3 Power saving SLEEP mode reduces the functionality of the module to a minimum and thus minimizes the current consumption to the lowest level SLEEP mode can be set with the AT CFUN command which provides the choice of the functionality levels lt fun gt O 1 5 6 7 or 8 For further details on power saving see 1 and 2 lf the module is in multiplexer mode it is not recommended to activate SLEEP mode with AT CFUN lt n gt For produc
20. ds conflicts e Call control A voice call can be initiated answered or ended on each channel See AT commands like ATD ATA or ATH Please note that ATH terminates each voice circuit switched data or fax call regardless on which logical channel ATH was executed for details see 2 e Phonebook access If you wish to write the same phonebook entry on two different channels at the same time please note that the last entry will be stored permanently All other data will be deleted e SMS read write and delete e Time settings Though the AT commands AT CALA and AT CCLK can be used on either channel the same time setting applies to all three channels It is only the alarm message lt text gt which may be specific to each channel The URC CALA will be issued only on the channel where the last alarm setting was made For details see 2 e Device locks set with AT CLCK e SIM card access e RF settings Example e An ongoing fax call has been established on channel 1 When answering an incoming voice call on channel 2 or 3 and terminating it the held fax call will be ended as well 3 1 4 Functions without channel dependencies The following functions or events may be ongoing independently on different channels e Unsolicited Result Codes URCs will generally be transmitted to all logical channels For example an incoming voice call is indicated by the URC RING on all three channels Incoming data calls are indicated on chan
21. e 36 Table 8 Coding of TestCommand Example ccccccecceecceeceeeceeeeeeceeeeeeceeeseeeeeeeeeaeeees 37 Mux_guide_ v05 Page 4 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 0 Document history This chapter reports modifications and improvements over previous versions of this document Preceding document Multiplexer User s Guide Version 03 New document Multiplexer User s Guide Version 05 Chapter What is new 1 1 Added further supported products 3 1 4 Modified remark on AT amp W 3 1 6 Added chapter Operation of a second physical serial interface ASC1 if applicable Preceding document Multiplexer User s Guide Version 03 New document Multiplexer User s Guide Version 05 Chapter What is new 1 1 Added further supported products 3 3 4 Restructured and revised all chapters ile Zions To contro SLEEP mode use PSC messages rather than entering AT CFUN lt n gt 5 1 6 4 Mux_guide_v05 Page 5 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 1 Introduction Siemens GSM engines support the basic option of the multiplexer according to the ETSI TS 101 369 GSM 07 10 Multiplexer Protocol This allows a mobile to run a triple session over a serial link interface Outside the GSM engine on the application side of the serial interface another multiplexer must be integrated in order to demultiplex the signal and
22. ed 4 2 6 Frame checking sequence field FCS The Frame Checking Sequence FCS is computed with the address control and length fields It is a field added to the end of a frame that contains transmission error checking information This field contains a value which is calculated by the source computer The receiving computer performs the same calculation If the receiving computer s calculation does not match the result sent by the source computer the packet is judged corrupt and discarded An FCS calculation is made for each packet Mux_guide_ v05 Page 20 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 5 State diagrams The multiplexer protocol is based on two state machines see Figure 4 One state machine initiates the setup of the logical channels while the other responds to the requests The GSM engine can only respond to requests A higher level for controlling the state machines is not implemented The procedure for setting up the two state machines the one for the customer uC and the one for the GSM engine is shown in Figure 5 and Figure 6 Executing the AT command AT CMUX 0 starts the switchover from AT command mode to the multiplexer protocol and parameterizes the multiplexer control channel DLCI 0 Both state machines are entering the DISCONNECTED state and immediately have the option of setting up the multiplexer control channel DLCI 0 and other logical channels The lo
23. epancies in results Furthermore all safety instructions regarding the use of mobile technical systems including GSM products which also apply to cellular phones must be followed Siemens or its suppliers shall regardless of any legal theory upon which the claim is based not be liable for any consequential incidental direct indirect punitive or other damages whatsoever including without limitation damages for loss of business profits business interruption loss of business information or data or other pecuniary loss arising out the use of or inability to use the Documentation and or Product even if Siemens has been advised of the possibility of such damages The foregoing limitations of liability shall not apply in case of mandatory liability e g under the German Product Liability Act in case of intent gross negligence injury of life body or health or breach of a condition which goes to the root of the contract However Claims for Damages arising from a breach of a condition which goes to the root of the contract shall be limited to the foreseeable damage which is intrinsic to the contract unless caused by intent or gross negligence or based on liability for injury of life body or health The above provision does not imply a change on the burden of proof to the detriment of the Recipient Subject to change without notice at any time The interpretation of this general note shall be governed and construed according to German law without
24. f requested channel Figure 7 DLC establishment 5 1 3 Information transfer A response is not essential for every command for example an unsolicited result code does not require a response UIH P 0 C R 1 Customer gt gt uC Initiator lt lt aaa P 0 C R 0 GSM engine Responder Figure 8 Information transfer Mux_guide_v05 Page 25 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 5 1 4 DLC release No provision is made to repeat the request if no response is received DISC P 1 Customer s GSM uC engine responding station is already disconnected Figure 9 DLC release 5 1 5 Turn off procedure To switch the multiplexer off the following procedures may be used e Disconnecting all DLCls DLCI command The last disconnection is for DLCI 0 e Multiplexer close down command CLD The multiplexer controls the close down all DLCls are closed first and finally DLCI 0 From this moment on both stations return to AT command mode 5 1 6 Multiplexer control channel DLCI 0 Type Length Value 1 Value 2 Value n 1 Octet n Octets 1 Octet 1 Octet 7 1 Octet Information Field Figure 10 Multiplexer control channel The commands are sent as information in the multiplexer control channel frame Mux_guide_v05 Page 26 of 37 17 12 2003 Multiplexer User s Gui
25. features from version 2 e Transparent signals DSR CTS RING and DCD e Send MSC request from module to host after version check on every channel to signal the initial state The table below summarizes the differences in handling the MSC using the various multiplexer protocol versions Modem status command MSC Command Length DLCI V 24 signals Break Signals optional 1 octet 1 octet 1 octet 1 octet 1 octet Command Bit4 Bit2 Bits Bit4 _ Bit5 Bit _ Bit7 __ Bit8 a oR Jo do do d A A Figure 14 MSC as used in version 3 Mux_guide_v05 Page 33 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile V 24 signals Bit4 Bit2 Bits Bit4 BitS Bit6 _ Bit7 __ Bit8 Table 6 Version differences for MSC Version RTC RTC RTC RING DCD no host application module module host application if O is indicated all calls are terminated DTR RTS DTR RTS DSR CTS RING DCD Please note that it is strongly recommended to use the latest version switched on by version control Examples for handling different versions from the Mux C gt C gt without version check 1 Multiplexer Protocol Version without version check with version check with version check old version old version with version check with version check new version new version Figure 15 Overview
26. gical channels are then set up DLC establishment If the DLC has been established successfully the state machine for that particular channel changes to CONNECTED In the case the request is unsuccessful the logical channel cannot be established and the state machine remains in DISCONNECTED on this particular channel Information can be transferred over all channels in CONNECTED Control commands can be transferred in the multiplexer control channel DLCI 0 the other channels transfer data The parameters for all logical channels DLCI 1 4 in DISCONNECTED can be set for the requested logical channels by parameter negotiation Disconnecting individual channels DLC release causes the state machine for those channels to revert to DISCONNECTED Release of the multiplexer control channel DLCI 0 corresponds to a CLOSE DOWN The CLOSE DOWN command switches back Mux_guide_ v05 Page 21 of 37 17 12 2003 Multiplexer User s Guide Confidential Released Customer uC Master state machine CLOSED DOWN Close Down t Up Close Down DLC parameter negotiation Close Down DIS CONNECTED NEGOTIATION DIS CONNECTED DLC Release DLC Establishment SIEMENS Mobile GSM engine uC Slave state machine CLOSED DOWN Close Down t Up Close Down DLC parameter negotiation Close Down DIS CONNECTED NEGOTIATION
27. into CYCLIC SLEEP mode like AT CFUN 6 1 1 Switches off like AT SMSO O PE P p FFF Switches into CYCLIC SLEEP mode like AT CFUN 7 pE p p pere AT CFUN 8 All wake up events and details of the CYCLIC and NON CYCLIC SLEEP mode are specified in 2 In responses Bit4 _ Bit2_ _ Bit3 _ Bit4 Description _ _ oo Jo Jo Fc ao JO Success No Value octet Length 0 Switches into SLEEP mode like AT CFUN 0 Note According to the GSM 07 10 standard PSC supports no value octets The optional value octet was added to increase flexibility Developed as a substitute to the AT CFUN command PSC messages are recommended to control the various SLEEP modes and to reset the mobile Be sure not to enter any PSC messages until after all responses to AT commands have been received and in the case of a received URC the logical ring line has been activated for 1 second and deactivated again Please note that the behavior of the logical ring line is identical with the behavior of the physical RINGO line described in 1 Mux_guide_v05 Page 30 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 5 1 6 5 Non supported command response NSC This response is sent whenever a command type is not supported by the receiving entity Type field Bit4 Bit2 _ Bit3 Bits Bits Bit _ Bit7 __ Bit8 ao oR Jo Jo i do do o C R bit Indicates whether the sequence is a command or a response Value oc
28. itched off If then for example a large amount of URCs is generated their transmission might be stopped due to the flow control To avoid this problem we recommend that you do not activate flow control on multiplexer channel 2 when you set up a user profile with AT amp W Mux_guide_ v05 Page 13 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 3 2 Multiplexer control and signaling lines The following chapter covers all information you need to develop and set up a virtual driver Differences and restrictions in comparison to the unframed module are pointed out 3 2 1 Flow control Logical flow control The internal logical flow control FC BIT in MSC message see Chapter 5 1 6 3 represents the existing flow control to the module For example if a data call is initiated and the customer application transmits data to the module on this channel the module will stop the data transmission from time to time This happens because the module operates with a bandwidth of 9k6 on air but the customer application uses a larger width In this case the module sends a MSC message with FC BIT set After all data stored in the internal buffer have been sent the module will send a second MSC message with FC BIT reset As already pointed out the logical flow control operates like RTS CTS but with FC BIT on every channel The RIS CTS are not used for flow control because the traffic on the logical channels may cause a tempor
29. l channel and the logical channel 5 2 2 Closing the multiplexer protocol and returning to AT mode The best and safest approach to power down the multiplexer is to issue the appropriate AT command for details see 2 This procedure sends a CLOSE DOWN request of the multiplexer control channel and allows the interface to return into AT command mode Mux_guide_v05 Page 32 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 6 Version control 6 1 Introduction The multiplexer protocol offers a version control which ensures that TE and MS side support the same state of functionality If you wish to implement the multiplexer protocol yourself keep in mind that it is absolutely necessary to implement the version check in the case you wish to use features included in later versions The implementation is a subset of the GSM 07 10 standards The version control also ensures the upward and downward compatibility of the GSM engine When the multiplexer is started the MS and the application negotiate which MP version to use 6 2 Multiplexer protocol versions This chapter briefly summarizes the various existing multiplexer protocol versions 1 No version check e No break signal is sent 2 First version including the version check e Additional features transparent signals DTR and RTS e escape sequence transportable via MSC 3 Advanced version included in all modules mentioned in Chapter 1 1 e All
30. le 2 2 Virtual channels and AT commands Please note that a cellular engine designed for multiplex operation does not include three different devices Only one single air interface RF part is available As mentioned before the multiplexer enables one serial interface to run three sessions simultaneously All incoming or outgoing calls are connected to the device Channel 1 supports the full range of functions which is available without multiplexer tool Channel 2 and 3 are connected to a different AT interpreter and support a subset of the functional range of channel 1 for more details refer to Table 1 Table 1 Comparison of multiplexer channels Voice calls Data fax calls SMS GPRS Phonebook AT incoming incoming incoming connection management commands outgoing outgoing outgoing Channel 1 o Channel 2 3 2 o o indicates that the functionality is available on the channel indicates that the functionality is not available on the channel 1 except for AT commands related to data and fax calls only two channels can be used parallel to transmit GPRS data Examples e While a data call is in progress on channel 1 you can send a short message on channel 2 and edit the phonebook on channel 3 e When receiving a fax on channel 1 you are able to check the battery capacity using the appropriate AT command on channel 2 or 3 Note Due to the technical requirements of multiplexer mode data and fax calls can onl
31. mavenyineweiasenninasinee 20 4 2 6 Frame checking sequence field FCS cccccccecceecceeeeeeeeeeeeeeeeeeeees 20 5 State diagrams rise tise tert epe se cai tere ettigt nc ee oe me sentra vente vee sewn eee seu anuesaeeneenwereste lt steeus 21 5 1 1 Start UP PrOCECUre ccecsusssssssecsccsccsccessussursursascesccecceseessursursassasess 25 SIZ DLOAD MIC orir ER 25 Ole IfomMmMauon transie wsanssceniecccasvaansacsnrqncearsaansndaniencannter vex eaeenseseen ence 25 DIA DLO TEC ASS srncaientensusdusaccaedsnmaraedwiacsausnanedeetinisalexannetetandhadenateanspanased ene 26 S19 mor OC CCAS sis a dented tend note A n 26 5 1 6 Multiplexer control channel cccccecceeceeseeeeeeeeeeceeseeseeeeeeeeeseeaeeees 26 5 1 6 1 Multiplexer close down CLD cccccceccsecceeeeeeceeeeeeeeeeseeseeeseeeeeseees 27 5 1 6 2 Test command Test ccccccccsccceeceeeceeeeeeceeeeeeceeeeeceeeeeseeeeeeseeesees 27 5 1 6 3 Modem status command MSC cccccccccceecseeceeeeeeeeeeeeeeeeeseeeeeseees 28 5 1 6 4 Power saving control PSC ccccccccecceeeeeceeeeeeteeeseeeeeeeeeeeeeseeseeeseees 29 5 1 6 5 Non supported command response NSC cccccceceeeeeeeeeeeeeeeeees 31 5 2 Samples of establishing logical Channels ccccccecececceeeseeceeeeeeeeeseeeeeesees 31 5 2 1 Establishing logical channels without parameter negotiation 31 5 2 2 Closing the multiplexer pro
32. na E E E E eee 26 Figure 10 Multiplexer control channel cccccccecceeceeeeeeeeeeeeseeceeceeeeeeeeeeeseeseeseeseeseesaeees 26 Figure 11 Modem status command MSC cccccceccececeeeeeeceeeeeeseeeeeeseeeeeeseeeeeseeseeeseeeaes 28 Figure 12 Power Saving Control PSC ccccccceccceeceeeceeseeceeceeeceeceeeseeseeeceeseeeseesaeeaeenaes 29 Figure 13 Establishing the multiplexer control channel and the logical channel 32 Figure 14 MSC as used in version 3 ccccecceecceeceeeceeceeececeeeceeceeeceeseseeesaesaeeseesaeeseesaeeeaes 33 Figure 15 Overview of combinations for version CNECK c ccccecceecceeeeecceeeeeeeeeeeeeeeeeaeeees 34 Tables Table 1 Comparison of multiplexer Channel s ccccccsecceeceeeeeeeeeeeeseeeeeeeeeeeeeeeneseeeeeeeees 10 Table 2 Address TC eects ee tt eset Sees ees eae nae dict EAKA Eiaa decease eee 18 Table 3 Assignment of the DLCL ccc cecccccceeceeeceeceeeceesaeseeecaeeaeeseeeaeecaeeseeseeeeeeseeesaees 18 Table 4 Use of the command response Dit ccecceccsecseeceeceeceeceeeeeeeeceeeseeeeeeeeeeeseeeeeeeees 19 Table 5 Coding of the Control field cc eccccccecceeeceeceeeceeeeeeceseeeceeseeeaeeceeeeeseeeeeeseeeaeeees 19 Table 6 Version differences for MSC cccccccccecceecceeeeecceeeeeececeeeseeseeeeeeseeeseeseeeseeseeeaeeees 34 Taner AE ole e 9 cee eenenee een eee nee een ee ee E E eee eee eee ee ee e
33. nel 1 only e Device information can be queried on a single channel e Signal quality and cell information can be retrieved on a single channel e Further commands that can be used separately on one channel without impact on the remaining channels ATZ AT amp F AT amp V AT CEER AT CMEE e User profile AT amp W stores the current setting of each channel to the user profile no matter on which of the three channels the command is executed Example e The battery capacity can be queried from channel 2 or 3 while a voice fax or data call is made on channel 1 Mux_guide_ v05 Page 12 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 3 1 5 Timing conditions Switching on the multiplexer with AT CMUX 0 causes a 5s timer to start If the multiplexer control channel is not established within this time the module returns to normal AT command mode without multiplexer This prevents the module from being blocked if for example AT CMUX 0 is sent from an application that does not support the multiplexer protocol Fax is based on a protocol which needs to respect timings between the application and the module as well as between the module and the selected terminal equipment TE Hence heavy parallel traffic load in the module can lead to mistiming This may result in malfunction in both directions Please consider the following recommendations Using the multiplexer it is not possible to define b
34. reference to any other substantive law Copyright notice Transmittal reproduction dissemination and or editing of this document as well as utilization of its contents and communication thereof to others without express authorization are prohibited Offenders will be held liable for payment of damages All rights created by patent grant or registration of a utility model or design patent are reserved Copyright Siemens AG 2003 Trademark notice MS Windows is a registered trademark of Microsoft Corporation Mux_guide_v05 Page 2 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile Contents 0 PO CUTS ING NISTO ser E E 5 1 UNE CUS UON saisreesseteces cee peers ee EE EA E EE E 6 1 1 Supported products and related COCUMENKS cccccecceeceeceeeeeeeeeeeeeeeseeeeeeseees T Vise RECIEN COS aa a tuto edie neha A E EE T 1 3 Term and abbreviatiOns igrescccncsestansceewencaasovanontstecsdeavensadsvennsdasondetnnsesinancenes 8 2 Multiplexer protocol an OVErViCW ccccceceeceeeeeceeceeeeeeescnseeseeseeeneonsoeseeceeoneaeseeees 9 2 1 Product concept and architecture cccccccccceccececeeeeeceeseeeeeeeceeseeeeeeeeseeeeeeeges 9 2 2 Virtual channels and AT COMMANGS ccccccceeceeeeeeeeeeeeeceeceeseeeeeeeeeceeseeaeees 10 3 Integrating multiplexer into the customer application ccccceseeeeeeeeeeeeeeeeeees 11 SF CHI CEI SUCS aoccrcccneanennsccacssansanc E E
35. s not received as expected the multiplexer stays in the state DLC_CONNECTEDWAIT4RESPONSE until another multiplexing related action takes place However it is possible to send test commands with any contents with exception of test messages with the specific IEI for the Version Check If a test command with any contents is sent it has to be sent back to the originator with the same contents 6 3 2 Coding of TestCommand message The coding of the multiplexer stack version is used specifically for SIEMENS equipment and is not defined in ETSI standards The IEI values defined for the verification pattern of the TestCommand message are indicated in Table 7 see GSM recommendation 07 10 Chapter 5 4 6 3 4 Table 7 IEI coding ret7 s 4 3 2 1 OCS re O O O TEMUX VERSION O O 1 O O MSMUX VERSION Other values reserved for future use For easier analysis of multiplexer traces the message shall be sent in the following format 1 Version IEl 2 TEMUXVERSION MSMUXVERSION send as ASCII 3 Version Number 1 999 send as ASCII The message part after the Version IEI is coded with ASCII characters So it is possible to read the version information from the trace file The version number must have a value between 1 999 If not all digits of the version number are used only the used digits are coded as ASCII sign s Digits that are not used are sent as zero string in the test message Mux_guide_v05
36. se TE and MS do not support the same multiplexer protocol version On TE side a version check is not included while the MS version already includes it Due to the implemented features the older protocol version will be used automatically 6 3 Implementation The TE initiates the version check by sending the test command message on DLCI 0 with TEMUX_Version As specified in the GSM recommendation 07 10 chapter 5 4 6 3 4 the opposite entity shall respond with exactly the same value bytes The MS should reply the test command response with the same contents for the verification pattern Hereafter the MS must send a test command message with MSMUX_Version to the TE which should be responded with the same contents After sending the response a comparison will be performed Please note that both sides should use the same multiplexer protocol version Mux_guide_v05 Page 35 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 6 3 1 Troubleshooting In the case the MS realizes the implemented software but the TE does not response correctly the following errors might occur e Request Test Message is not sent from TE side No Version check takes place No retransmission for Request Test Message is triggered The multiplexer is started with the lower version e Response Test Message is not sent from TE side No timer has been implemented for the non responding cases If the response message i
37. tet Bit4 Bit2 _ Bit3 _ Bit4 Bits Bit Bit7 _ Bit8 C R bit Returns the same value as in the received non supported command Frames not recognized by the receiving entity are responded by a NSC frame 5 2 Samples of establishing logical channels 5 2 1 Establishing logical channels without parameter negotiation e Send AT CMUX 0 wait for the response e Send Request SABM for DLCI 0 wait for the response e Send Request SABM for all requested DLCls wait for the response As a result the multiplexer is established and information data can be transmitted gt ready for Information Transfer Mux_guide_v05 Page 31 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile Serial interface Customer GSM engine pC uC RequestStartUp gt IndicationStartUp gt Start Up AT CMUX lt ResponseStartUp _ ConfirmStartUp Disconnected Disconnected DLCI 0 DLCI 0 RequestSABM DLCI 0 0 _ IndicationSABM DLCI 0 ResponseUA ConfirmUA peco DLCI 0 Connected Connected DLCI 0 DLCI 0 LC Establishment Create DLCI Disconnected Disconnected DLCI 1 DLCI 1 RequestSABM a DLCI 1 IndicationSABM DLCI 1 ResponseUA ConfirmUA K DLCI 1 DLCI 1 LC Establishment Create DLCI 1 Connected Connected DLCI 1 DLCI 1 Figure 13 Establishing the multiplexer contro
38. tocol and returning to AT mode 32 Mux_guide_v05 Page 3 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 6 Version CONO bsec aa a 33 OA MOUGU 0 eese ne E EEE E EA E E 33 6 2 Multiplexer protocol Versions cccccccecseceeceeceeceeeeeeeceeceeseeeeceeeeeeeseeseeeeeseeeeaes 33 Oa ONE O E R E 35 6 3 1 TrOUDIO SNOOTING ccccccecceeceeceeseecaeceeeceeceeceeseesuesesaeeceeseesensensaeeas 36 6 3 2 Coding of TestCommand MeSSAGE ccccceecceeeeeeeeceeeeeeeeeeeeeeeaeees 36 6 3 3 Example of TestCommand message ccccecceecceeeeeeeeeeeeeeeeaeees 37 Figures Figure 1 Multiplexer architecture cccccccccecceeceeceeseeceeceeccueceeceeceeseesuesauseeeceeceesaesensansaees 9 Figure 2 Logical flow control and RTS CTS signaling behind the decoder 006 15 Figure Data liNK layer sosea a E EE Da 17 Figure 4 Relationship between the customer uC and the GSM engine HC assasonossenononeenennn 22 Figure 5 MPI Startup DLC establishment and information transfer ccccccseeeeeeeees 23 Figure 6 MP DLC release and close down ccccecceccceeceeeceeeeeeceeeeeeceeeeeeeeeeeeseeeseeeaeeeaes 24 Figure 7 DLC establishment ccccccccccceccecceeeeeeceeeeeeceeeseeseeceeeseeceeeseesseeseeeeeeeeeseeseesaes 25 Figure 8 Information transfer esisiini a ri ra ir r EEEE NiE 25 Foue o DEC TOG E ar
39. ts supporting Multiplexer Protocol version 3 the best approach to properly control SLEEP mode in this case is to issue the PSC messages described in Chapter 5 1 6 4 3 4 Bandwidth of logical channels Please take into account that a data transmission e g on channel 1 causes a transmission delay on the remaining channels see chapter 3 1 The multiplexer mode according to the GSM 07 10 multiplexer protocol encapsulates data and AT commands into packets which may vary in length Therefore a header including protocol information located at the beginning of the protocol data unit has to be transmitted To summarize if the module is set to 115200 bps and an incoming GPRS call requires 5 kByte per second the two other channels have to operate within the range of the remaining 5 kByte per second If three large data transmissions are running simultaneously the available bandwidth will be shared equally among all channels In such a case if channel 2 and 3 were used for data transmissions e g editing the phonebook both channels would need to share a bandwidth of approximately 3 kByte per second Mux_guide_ v05 Page 16 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 4 Structure of the multiplexer protocol 4 1 Introduction of the multiplexer protocol The supported multiplexer protocol conforms to the GSM 07 10 Multiplexer Protocol The non error recovery mode was implemented with the basic option The
40. will be stored in the non volatile memory and used whenever the module is powered up again In this case the multiplexer fails to start To avoid this it is recom mended to re synchronize all settings before using the multiplexer mode again 3 1 2 Restrictions If the GSM engine is operated in multiplexer mode the following restrictions apply e MO and MT circuit switched data and fax calls can only be set up on channel 1 e It is not recommended to use AT CFUN lt n gt for selecting one of the SLEEP modes For products supporting Multiplexer Protocol version 3 the best approach to properly control SLEEP mode in this case is to issue the PSC messages described in Chapter 5 1 6 4 The multiplexer cannot be started if one of the following features is activated nor can these features be used when multiplexer is active e Multiplex mode cannot be started while autobauding AT IPR 0 is enabled e The multiplexer is not available in charge only mode and in alarm mode e XON OFF flow control is not supported in multiplexer mode Mux_guide_ v05 Page 11 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 3 1 3 Dependencies between multiplexer channels and restrictions of use When using the following functions be aware of possible dependencies between the different channels One way of avoiding problems may be to dedicate certain commands features to one of the channels or to assure that the application avoi
41. y be set up on logical channel 1 while GPRS connections can be established on every channel Several AT commands have a different behavior on channels 2 and 3 Additional information regarding restrictions and interferences between the channels can be found in chapter 3 1 and in 2 Mux_guide_ v05 Page 10 of 37 17 12 2003 Multiplexer User s Guide SI EM ENS Confidential Released Mobile 3 Integrating multiplexer into the customer application When designing a multiplexer application you can create your own sources or take advantage of the sources delivered upon request by Siemens The Siemens sources are packed in a zip file which includes a driver for Windows 2000 and Windows XP See 5 for a detailed description 3 1 Characteristics After establishing the multiplexer mode according to the multiplexer protocol three logical channels are available Please keep the following restrictions and requirements in mind 3 1 1 Basic requirements e The GSM engine supports the basic option and UIH Framing according to GSM 07 10 e Character framing must be configured for 8 data bits no parity and 1 stop bit If you wish to use multiplexer mode with TC35i modules be sure not to change this setting e Hardware flow control AT Q3 is recommended for use with multiplexer mode If used it needs to be set before multiplexer mode is entered e Several customer software applications may be able to change the selected settings These settings
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