SIM900_Multiplexer User Manual_Application Note_V1.3
Contents
1. Wl ET 13 2 94 MSC ossis ah eta ot ear t Hed eda da a Fees d Ea test e e ss 13 De WACOM Goose idibus ni ted see cen E unde iu 14 2 5 6 Igor eci 14 2 9 5 PNsNSCs REN RES SNQ isset teen terrre reed en 14 2 6 Data Channel oie RET RR RO ERR ERRORES RR TREO FRE EE ERE 15 Ade About Flow Control ei eee e e EE RERO T e ERE EET edo 16 2 8 Samples for Frame Structure eere en rennen 17 2 9 Iransmission bit sequence eren roe eere b ren ea e eve e ere 17 3 JBXxamples cesses rte ER E E EEG e cease Da FO Rea P E FECE E FU ET Go repe is 18 34 Establish Channels uere e e e e ERRARE REPRE er EE v E Rete 18 3 2 BrameIranstmissioti eter i EE pe EE e REV e EXER RETINA EE X ET REV Se e E es 21 3 3 Power Saving Mode and Wake Up nennen 22 344 Blow Connon coe RO RR RE EROR REA RARE tat matei 23 3 5 Dealing with the wrong frame enne eene isernia 24 3 6 Closing Down Multiplexers eeeeeeeeseeeeeeee eene eene en enr 25 SIM900 Multiplexer User Manual Application Note V1 3 3 2010 11 07 SIM900 Multiplexer User Manual Application Note Version History SIM900_Multiplexer User Manual_Application Note_V1 3 4 2010 11 07 SIM900 Multiplexer User Manual Application Note wi Com Abbreviations DLC Data Link Connection DLCI Data Link Connection Identifier RLS Remote Line Status Command SABM Set Asynchronous Balanced Mode UA Unnumbered Acknowledgement DM Disconn2. DLC Establishment The establishment of a DLC will be initiated by the TE TE wishing to establish a DLC transmits a SABM frame with the P bit set to 1 The address field contains the DLCI value associated with the desired connection If MS is ready to establish the connection it will reply with a UA frame with the F bit set to 1 If MS is not ready or unwilling to establish the particular DLC it will reply with a DM frame with the F bit set to 1 Please refer to 3 1 for more details 2 4 Closing Down DLC The release of a DLC will be initiated from by the transmission of a DISC frame with the P bit set to 1 Confirmation of the DLC release is signaled by MS sending a UA frame with the F bit set to 1 Once the DLC has been released the MS enter disconnected mode for that particular DLC If MS receiving the DISC command is already in a disconnected mode it will send a DM response Please refer to 3 6 for more details 2 5 Control channel Multiplexer control channel is the basic channel which is used to establish DLC launch power saving wake up from power saving and implement flow control mechanism Control channel is the first channel established at the initiation of the multiplexer between the TE and MS and it has the DLCI value 0 UIH message frame is transmitted through control channel All UIH message frame conform to the following format Type Length Value 1 Value2 Value n Each box in t
3. is defined as a constant bit pattern OxF9 2 1 2 Address Field The address field consists of a single octet It contains the Data Link Connection Identifier DLCD the C R bit and the address field extension bit EA as following table Bit 1 2 3 4 5 6 7 8 EA CR D L C I The range of the address field may be extended by use of the EA bit When the EA bit is set to 1 in an octet it signifies that this octet is the last octet of the address field When the EA bit is set to 0 it signifies that another octet of the address field follows SIMCOM multiplexer only supports one address octet so the EA bit is always set to 1 The C R command response bit identifies the frame as either a command or a response The DLCI is used to identify an individual data stream as well as channels between TE and MS Multiple DLCIs shall be supported but the number is implementation specific The DLCIs are dynamically assigned 2 1 3 Control Field The content of the control field defines the type of frame The control fields of the frames used in the present document are described in the following table SIM900 Multiplexer User Manual Application Note V1 3 8 2010 11 07 Hs EN SULL Com SIM900 Multiplexer User Manual Application Note A company of SAA Tec Bit 1 2 3 4 5 6 7 8 HEX 1 Frame Type Comment Set Asynchronous 1 1 1 1 P F 1 0 0 O
4. ABM SABM is command frame and shall be used to establish DLC between TE and MS Please refer to 3 1 for more details 2 2 2 UA UA frame is the response to SABM or DISC frame Please see following diagram and refer to 3 1 and 3 6 for more details SABM Set up DLC 1 UA Response DISC Close DLC 1 Multiplexer Receiver UA Response 2 2 3 DISC DISC is command frame and shall be used to close down DLC Prior to acting the command the receiving station shall confirm the acceptance of the DISC command by the transmission of a UA response Please see the diagram above and refer to 3 6 for more details 2 2 4 DM The DM response frame shall be used to report a status whether the station is logically disconnected from the data link When in disconnected mode no commands are accepted until the disconnected mode is terminated by the receipt of a SABM command If a DISC command is received while in disconnected mode a DM response should be sent Please refer to 3 1 for more details SIM900 Multiplexer User Manual Application Note V1 3 10 2010 11 07 SIM900 Multiplexer User Manual Application Note A company of SBA Tec 2 2 5 UIH The UIH command response shall be used to send user data at either station Please refer to 3 2 for more details 2 2 6 UI Not support SIM900 Multiplexer User Manual Application Note V1 3 11 2010 11 07 T SUL Com SIM900 Multiplexer User Manual Application Note A company of SAA Tec 2 3
5. Bi Ses Co A company of SIM Tech SIM900 Multiplexer User Manual Application Note V1 3 f o 2vision Note Application Note E A company of SIM Tech SIM900 Multiplexer User Manual Application Note General Notes SIMCom offers this information as a service to its customers to support application and engineering efforts that use the products designed by SIMCom The information provided is based upon requirements specifically provided to SIMCom by the customers SIMCom has not undertaken any independent search for additional relevant information including any information that may be in the customer s possession Furthermore system validation of this product designed by SIMCom within a larger electronic system remains the responsibility of the customer or the customer s system integrator All specifications supplied herein are subject to change Copyright This document contains proprietary technical information which is the property of SIMCom Limited copying of this document and giving it to others and the using or communication of the contents thereof are forbidden without express authority Offenders are liable to the payment of damages All rights reserved in the event of grant of a patent or the registration of a utility model or design All specification supplied herein are subject to change without notice at any time Copyright Shanghai SIMCom Wireless Solutions Ltd 2010 SIM900 Multiplexer User Manual Ap
6. F9 07 73 00 00 D7 F9 accept TE sends DISC frame to request FO 0b 53 01 B8 F9 closing down DLC 2 MS feeds back UA frame to F9 Ob 73 00 00 42 F9 accept TE sends DISC frame to request F9 0f 53 01 3f F9 closing down DLC 3 MS feeds back UA frame to F9 Of 73 00 00 31 F9 accept TE sends DISC frame to request F9 13 53 01 3f F9 closing down DLC 4 MS feeds back UA frame to F9 13 73 00 00 A9 F9 accept TE sends CLD message frame to F9 03 EF 05 C301 F2 request closing down multiplexer F9 through DLC 0 MS feeds back CLD response to F9 01 EF 04 00 C1 01 accept D3 F9 By now closing down procedure is over SIM900_Multiplexer User Manual_Application Note_V1 3 25 2010 11 07 SULL Com SIM900 Multiplexer User Manual Application Note Contact us Shanghai SIMCom Wireless Solutions Ltd Add Building A SIM Technology Building No 633 Jinzhong Road Changning District Shanghai P R China 200335 Tel 86 21 3235 3300 Fax 86 21 3235 3301 URL www sim com wm SIM900_Multiplexer User Manual_Application Note_V1 3 26 2010 11 07
7. Response Timer for wake up station of a power wake up procedure command waits before raising an alarm when no response is received K N A Not used Window Size UI Frames are not supported Only supports GSM 0710 Basic Option 1 4 References Y Digital cellular telecommunications system Phase 2 Terminal Equipment to Mobile Station TE MS multiplexer protocol GSM 07 10 version 7 1 0 Release 1998 Y SIMCOM AT Commands Set SIM300 ATC V2 00 SIM900 Multiplexer User Manual Application Note V1 3 7 2010 11 07 Hs T SUL Com SIM900 Multiplexer User Manual Application Note A company of SAA Tec 2 SIMCOM Multiplexer Protocol SIMCOM Multiplexer protocol provides a data transmission mechanism by establishing DLC between TE and MS Several DLC can be set up Each one is independent to one another and has its own management of buffer and flow control All information transmitted between the TE and MS is conveyed in frames 2 1 Transmission Frame Structures The frame structure is composed of an opening and a closing flag an address field a control field a Length field an information field and FCS field Please see following table Opening Address Control Length Information FCS Closing Flag Field Field Field Field Field Flag 1 byte 1 byte 1 byte 2 byte Multi byte 1 byte 1 byte 2 1 1 Opening and Closing Flag Field Each frame begins and ends with a flag sequence octet which
8. age F9 01 EF OB E3 07 0B OD frames 01 79 F9 MS feeds back MSC F9 01 EF 0A 00 E1 05 07 response OB OD 01 96 F9 4 Establishment of DLC 3 4 are the same as above 5 By now 4 channels have come into existence Multiplexer can work normally Note 1 This SABM is transmitted in order to determine whether MS is using Standard or Embedded Multiplexer 1 MS is using Standard Multiplexer if responds with DM frame 2 MS is using Embedded Multiplexer if responds with UA frame SIM900 Multiplexer User Manual Application Note V1 3 19 2010 11 07 SIM900 Multiplexer User Manual Application Note Here is Standard Multiplexer SIM900 Multiplexer User Manual Application Note V1 3 20 Su Com 2010 11 07 SIM900 Multiplexer User Manual Application Note A company of SIM Tech 3 2 Frame Transmission After establishment of control channel and data channels TE and MS can transmit data through UIH frames between each other 1 TE sends AT FO 05 EF 09 41 54 49 0D 58 F9 UIH Frame command ATI lt CR gt through DLC 1 MS feeds F9 05 EF 08 00 41 54 49 OB 3F F9 F9 UIH Frame back through 05 EF 20 00 0D 0A 53 49 4D 39 30 30 DLC 1 20 52 31 31 2E 30 OD OA FF F9 F9 05 EF 0C 00 OD 0A 4F 4B OD 0A 4A F9 2 TE sends AT F9 09 EF 07 41 54 0D 35 F9 UIH Frame command AT lt CR gt through DLC 2 MS feeds F9 09 EF 06 00 61 74 0D EF F9 F9 09 EF UIH Fram
9. be used to transmit user data streams such as AT command data GPRS data and GSM CSD data streams Data channels shall be established after and only after control channel DLCI 0 connected Please refer to 3 1 for more details SIM900_Multiplexer User Manual_Application Note_V1 3 15 2010 11 07 SIM900 Multiplexer User Manual Application Note y oe 2 7 About Flow Control SIMCOM multiplexer supports software flow control and can not perform hardware flow control mechanism Software flow control is implemented by GSM 0710 MSC FCoff and FCon message frame MS will send MSC message to TE with FC bit set to 1 in V 24 control signals when refuse to accept frames Whereas set to 0 to inform recovery of receiving frames TE will send MSC message to MS with FC bit set to 1 in V 24 control signals when refuses to accept frames Whereas set to 0 to inform recovery of receiving frames When receiving MSC MS will feed back MSC response to indicate recover data transmission TE also can send Fcoff message to MS when refuses accept anything except control messages on DLC 0 After this MS will stop sending any frames through all the data channels except control channels Control channel is still alive and free to send any control message Whereas sends FCon to recover transmission When receiving Fcoff or FCon message MS will feed back Fcoff or FCon response The difference between MSC and Fcon Fcoff is that the former only flow controls
10. ding octet 1 2 3 4 5 6 7 8 EA C R 0 0 0 1 1 1 Hex value is OXE3 Command OxEI Response The EA bit is always set the 1 The C R bit is used to indicate if it is a Modem Status Command or Modem Status Response In a Modem Status Command it is the status of the sender s own V 24 signals that shall be sent but in a Response it is copy of the V 24 signals that are received from the Command frame that shall be returned The DLCI field identifies the specific DLC to which the command applies EA bit are always set to 1 V 24 control signals format is 1 2 3 4 5 6 7 8 EA FC RTC RTR reserved 0 reserved 0 IC DV Break signals is set to 0x01 2 5 5 FCoff Message type coding octet is 1 2 3 4 5 6 7 EA C R 0 0 0 1 1 0 Hex value is 0x63 Command 0x61 Response The length byte contains the value 0 and there are no value octets 2 5 6 FCon Message type coding octet is 1 2 3 4 5 6 7 8 EA C R 0 0 0 1 0 1 Hex value is OxA3 Command OxA1 Response The length byte contains the value 0 and there are no value octets 2 5 7 PN NSC RPN RLS SNC Not Supported SIM900_Multiplexer User Manual_Application Note_V1 3 14 2010 11 07 I ae SUL Com SIM900 Multiplexer User Manual Application Note A company of SAA Tech 2 6 Data Channel SIMCOM multiplexer data channels shall
11. e back through OC 00 OD 0A 4F 4B OD 0A DF F9 DLC2 3 DLC3 4are same as above SIM900 Multiplexer User Manual Application Note V1 3 21 2010 11 07 SIM900 Multiplexer User Manual Application Note 3 3 Power Saving Mode and Wake Up Power saving 1 TE sends PSC message F9 03 EF 05 4301 F2 F9 PSC Command through DLC 0 Frame MS feeds back PSC F9 03 EF 05 41 01 F2 F9 PSC Response message through DLC 0 Frame MS enters power saving Note mode Note Power Saving Mode could be launched after AT CSCLK 1 and then set DTR high Wake up Set DTR low SIM900 Multiplexer User Manual Application Note V1 3 22 2010 11 07 SIM900 Multiplexer User Manual Application Note 3 4 Flow Control MS sends MSC message with FC bit set tol through control channel DLC 0 to indicate refusing to accept anything on DLC 1 F9 01 EF 0B E3 07 07 8F 01 79 F9 MS sends MSC message with FC bit set to 0 through control channel DLC 0 to indicate recovery of DLC 1 data transmission F9 01 EF OB E3 07 07 8D 01 79 F9 TE sends MSC message with FC bit set tol through control channel DLC 0 to indicate refusing to accept anything on DLC 1 F9 01 EF 0B E3 07 07 8F 01 79 F9 TE sends MSC message with FC bit set to 0 through control channel DLC 0 to indicate recovery of DLC 1 data transmission F9 01 EF 0B E3 07 07 8D 01 79 F9 TE sends FCoff message t
12. ected Mode DISC Disconnect DISC command UIH Unnumbered information with header check UIH command and response UI Unnumbered Information command and response PSC Power Saving Control CLD Multiplexer Close Down MSC Modem Status Command TE Terminal Equipment MS Mobile Station FC Flow Control RTC Ready To Communicate RTR Ready To Receive IC Incoming Call Indicator DV Data Valid PN Parameter Negotiation FCon Flow Control On Command FCoff Flow Control Off Command NSC Non Support Command RPN Remote Port Negotiation RLS Remote Line Status Command SNC Service Negotiation Command TE Terminal Equipment MS Mobile Station SIM900 Multiplexer User Manual Application Note V1 3 5 2010 11 07 T SLL Com SIM900 Multiplexer User Manual Application Note A company of SAA Tec 1 Introduction The present document describes the SIMCOM multiplexer protocol and the technical details of how to make use of it 1 1 SIMCOM Multiplexer Design Purpose A device using GPRS or GSM data may wish to receive and transmit multiple streams of data simultaneously These are Command data AT commands GPRS data and GSM circuit switched data CSD These streams are essentially independent to one another As to the non multiplexer device it is so inefficient to deal with only one kind or one channel of data steam during a period of time Therefore SIMCOM multiplexer is designed with GSM0710 standard to separate transmissio
13. es MS 61 74 2B 63 6D 75 78 AT CMUX 0 lt CR gt lt LF gt multiplexer 3D 30 0D OD 0A 4F 4B function by AT OD 0A OD 0A command MS feed back 61 74 2B 63 6D 75 78 AT CMUX 0 lt CR gt lt LF gt response 3D 30 OD OD 0A 4F 4B OK lt CR gt lt LF gt lt CR gt lt LF OD OA OD 0A gt Host need quickly send the establish DLCO frame otherwise the client will exit MUX state Step 2 Establish DLC 0 1 TE requests to Establishes F9 03 3F 01 1C F9 SABM Frame control channel DLCI 0 using SABM frame MS feeds back UA for F9 03 73 00 00 A4 UA Frame receiving SABM and accepts F9 to create DLCI 0 SIM900 Multiplexer User Manual Application Note V1 3 18 2010 11 07 SIM900 Multiplexer User Manual Application Note Step3 Establish DLC 1 2 RE ges eer Gee SULL Com A company No Step Data Hex Comment Direction TE 2M S 1 TE requests to establish F9 07 3F 01 DE F9 DLCII using SABM frame MS feeds back UA for F9 07 73 00 00 D7 F9 receiving SABM and accepts to create DLCI 1 2 TE sends MSC message F9 01 EF OB E3 07 07 OD frames 01 79 F9 MS feeds back MSC F9 01 EF 0A 00 E1 05 07 response OD 01 96 F9 3 TE requests to establish F9 0B 3F 01 59 F9 DLCD using SABM frame MS feeds back UA for F9 OB 73 00 00 42 F9 receiving SABM and accepts to create DLCI 2 TE sends MSC mess
14. he table represents a field of minimum size one octet The first type field octet has the following format 1 2 3 4 5 6 7 8 EA C R Tl T2 T3 T4 T5 T6 The EA bit is an extension bit It is set to 1 in the last octet of the sequence In other octets EA is set to 0 SIMCOM multiplexer only supports one octet is transmitted So EA is always set to 1 The C R bit indicates whether the message is a command or a response The T bits indicate the type coding Each command has a unique pattern of bit sequence This means that a single octet type field can encode 63 different message types Only single octet message types are defined in the present document Please refer 2 5 1 to 2 5 6 fore more details The length field octet has the following structure 1 2 3 4 5 6 7 8 EA Ll L2 L3 L4 L5 L6 L7 The EA bit is an extension bit It is set to 1 in the last octet of the sequence In other octets EA is SIM900 Multiplexer User Manual Application Note V1 3 12 2010 11 07 T SUL Com SIM900 Multiplexer User Manual Application Note A company of SAA Tec set to 0 SIMCOM multiplexer only supports one octet is transmitted So EA is always set to 1 The L bits define the number of value octets that follows L1 is the LSB and L7 is the MSB this permits messages with up to 127 value octets to be constructed The message frame is divided into fol
15. hrough DLC 0 to indicate refusing to accept anything on all DLC except DLC 0 F9 01 EF 05 6301 93 F9 TE sends FCon message through DLC 0 to indicate recovery of data transmission F9 01 EF 05 A3 01 93 F9 SIM900 Multiplexer User Manual Application Note V1 3 23 2010 11 07 dE Rie 3 5 Dealing with the wrong frame After successful establishment of data channels Data transmission between TE and MS is normal SE es i eo 1 TE sends hex value OxF1 Fl Note 1 2 TE tests AT command F9 05 EF 07 41 54 0D 06 transmission through DLC 1 F9 after re sync MS feeds back response and F9 05 EF 07 41 54 0D 67 synchronization has been F9 F9 25 EF 0D 0D 0A 4F reset to normal 4B 0D 0A 8A F9 Note 1 Sending illegal hex byte will lead MS to receive a wrong frame Note 2 When receiving illegal hex byte between frames MS will just throw it away automatically and waiting for the next frame If next Frame is legal the Multiplexer will handle it and MS will give you a right response If not the Multiplexer will still throw it away and wait for the next frame SIM900 Multiplexer User Manual Application Note V1 3 24 2010 11 07 SIM900 Multiplexer User Manual Application Note 3 6 Closing Down Multiplexers TE sends DISC frame to request F9 07 53 01 3f F9 closing down DLC 1 MS feeds back UA frame to
16. lowing types 2 5 1 PSC Message type coding octet 1 2 3 4 5 6 7 8 EA C R 0 0 Hex value is 0x43 Command 0x41 Response The EA bit is always set to 1 The length field in PSC message frame is 0 It has no value octet 2 5 2 CLD Message type coding octet 1 2 3 4 5 6 7 8 EA C R 0 0 0 0 1 1 Hex value is OxC3 Command OxC1 Response The EA bit is always set the 1 The length field in CLD message frame is 0 It has no value octet 2 5 3 Test Message type coding octet 1 2 3 4 5 6 1 EA C R 0 0 0 1 0 0 Hex value is 0x23 Command 0x21 Response The EA bit is always set the 1 The test command is used to test the connection between MS and the TE The length byte describes the number of value bytes which are used as a verification pattern The opposite entity shall respond with exactly the same value bytes 2 5 4 MSC MSC message frame is designed to convey virtual V 24 control signals It has one mandatory control signal byte and an optional break signal byte MSC shall be sent prior to any user data after a creation of a DLC SIM900_Multiplexer User Manual_Application Note_V1 3 13 2010 11 07 Hs I SLL Com SIM900 Multiplexer User Manual Application Note A company of SAA Tec Message format is Type Length DLCI V 24 control signals Break signals Optional Message type co
17. n device layer into several logic channels DLC in order to transmit data simultaneously Each channel has its own buffer management and flow control mechanism 1 2 Architecture Diagram SIMCOM multiplexer architecture diagram is as following ERN Transmission Device 0 WemmssonDeoelayeiSeialPon Serial Port Client Application SIMCOM Multiplexer is established upon system transmission device layer Commonly serial port Data streams are addressed with DLCI value and encapsulated in frames based on GSM 0710 protocol Chapter 2 SIMCOM Multiplexer Protocol and transmitted through interface provided by transmission device layer SIM900 Multiplexer User Manual Application Note V1 3 6 2010 11 07 SIM900 Multiplexer User Manual Application Note y hoon 1 3 Restrictions Error Recovery Mode is not supported PN NSC RPN RLS SNC message frames are not supported Allthe system parameters defined in GSM 0710 are set to default as following table Parameter Value Comment TI 100 milliseconds Time that a station will wait for Acknowledgement Timer an acknowledgement before resorting to other action NI 255 Maximum number of octets that Maximum Frame Size that may be contained in an information field N2 3 Not used Maximum number of retransmissions T2 300 milliseconds Not used Response Timer for multiplexer control channel T3 10 seconds Amount of time the transmitting
18. one of the data channels and the latter controls all the data channels except controls channel Please refer to 3 4 for more details SIM900 Multiplexer User Manual Application Note V1 3 16 2010 11 07 SIM900 Multiplexer User Manual Application Note 2 8 Samples for Frame Structure Su Com Sample 1 F9 03 3F 01 1C F9 Opening Flag Address Control Field Length Field FCS Closing Flag Field Header DLCI 0 SABM Frame 0 no information Tail filed This sample is a SABM frame to open DLCI 0 Sample 2 F9 05 EF 09 41 54 49 0D 58 F9 Opening Address Control Length Information FCS Closing Flag Field Field Field Field Flag Header DLC 1 UIA 4 AT Command Tail Frame ATI lt CR gt This sample is a UIH frame to transmit AT command ATI lt CR gt Sample 3 F9 01 EF 0B E3 07 07 0D 01 79 F9 Opening Address Control Length Information FCS Closing Flag Field Field Field Field Flag Header DLC 0 UIA 3 MSC Message Tail Frame length 3 This sample is a MSC message carried in UIH frame to transmit V2 4 signal OxOD 2 9 Transmission bit sequence Transmission is based on 1 start bit 8 data bits 1 stop bit and no parity SIM900 Multiplexer User Manual Application Note V1 3 17 2010 11 07 SIM900 Multiplexer User Manual Application Note 3 Examples 3 1 Establish Channels _ Step Launch Multiplexer 1 TE launch
19. plication Note V1 3 2 2010 11 07 SIM900 Multiplexer User Manual Application Note Content Version HIStory Siu ERE HR ERE EAE ERU EE ERE EUH HH 4 i Introductions sits 6 1 1 SIMCOM Multiplexer Design Purpose ener 6 1 2 Architecture Diagrams pe re tede ee e qe ee e d reo E 6 IEEE URDU CN 7 E REeferenceS sie ies esa E us tient e eei 1 2 SIMCOM Multiplexer Protocol te ett a epp P Reine 8 2 1 Transmission Frame Structures eee erre nee n erede Ha EE NEU HEN OERE ES 8 2 1 Opening and Closing Flag Field eeeseseseseeeeeeenen 8 2 1 2 Address Field etre E 8 2 1 3 Control Bield 5 iet RR RRERR A KE NEAR ERAS PENES 8 2 4 Lenth Field osorioi dtt e be eoe 9 215 Information Fields M 9 2 2 rame Type suiro pre ir en e Hyde ie Pee er ev E HAE pe iv tees 10 2 2 1 SABM xn vise eene RI PRO ERE OPER CERDO ER HEHRS 10 DDD MA stove rette eei d t HR te Ev vete tesis 10 Ds JDISCL iuuenum tuts 10 224 DMLadscacsetddd dete eniti erre see s o ee ree ae ede 10 Dad UBL iiec ser pti p o EO e I E POTE EGO ELO CER TPO ERE TE ATE Hd 11 2207 IBI cuoco eter LM I ton Mu LEM TL 11 223 DLCBstablishinentz a e re LI ee elementals 12 DA Closing Down DEG oen hm miento rere ie epe enter E Y e 12 2 2 Control channel esed Ae EUR REIR OR ERREUR ERREUR FERREA ee el 12 258 PM Go E A E E NE se 13 2 952 QLDiiueenu eB RE ME da IRL SEI A Lore 13 2 35 3
20. x2F SABM Balanced Mode Unnumbered 1 1 0 0 P F 1 1 0 0x63 UA Acknowledgement 1 1 1 1 P F 0 0 0 OxOF DM Disconnected Mode 1 1 0 0 PF 0 1 0 0x43 DISC Disconnect Unnumbered 1 1 1 1 P F 1 1 1 OxEF UIH Information with Header check Unnumbered 1 1 0 0 PF 0 0 0 0x03 UI Information Not supported Note 1 Hex value does not count the bit 5 value 2 1 4 Length Field This field is present only in case when basic option is activated Bit 1 2 3 4 5 6 7 8 EA L1 L2 L3 L4 L5 L6 L7 The L1 to L7 bits indicates the length of the following data field The range of the length field may be extended by use of the EA bit When the EA bit is set to 1 in an octet it is signifies that this octet is the last octet of the length field When the EA bit is set to 0 it signifies that a second octet of the length field follows SIMCOM multiplexer only supports two length octet so the EA bit is always set to O Note Length field should always be contained in each frame even though information field is empty 2 1 5 Information Fields The information field is the payload of frame and carries the user data information e g AT Command and PPP data packet The field is octet structured The information field is only present in UIH frames SIM900 Multiplexer User Manual Application Note V1 3 9 2010 11 07 RE eer eer Ges SULL Com SIM900 Multiplexer User Manual Application Note A company 2 2 Frame Type 2 2 1 S
Download Pdf Manuals
Related Search