Multiplexer User's Guide
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mo b i l e
Mux_guide_v06 Page 3 of 36 30.06.2004
Contents 0 Document history..........................................................................................................5
1 Introduction...................................................................................................................6
1.1 Supported products and related documents..........................................................7
1.2 References ............................................................................................................7
1.3 Term and abbreviations.........................................................................................8
2 Multiplexer protocol – an overview............................................................................. 9
2.1 Product concept and architecture..........................................................................9
2.2 Virtual channels and AT commands....................................................................10
3 Integrating multiplexer into the customer application............................................ 11
3.1 Characteristics.....................................................................................................11
3.1.1 Basic requirements................................................................................ 11
3.1.2 Restrictions............................................................................................ 11
3.1.3 Dependencies between multiplexer channels and restrictions of use... 12
3.1.4 Functions without channel dependencies..............................................12
3.1.5 Timing conditions...................................................................................13
3.1.6 Operation of a second physical serial interface ASC1 (if applicable).... 13
3.2 Multiplexer control and signaling lines.................................................................14
3.2.1 Flow control............................................................................................14
3.2.2 Escape sequence.................................................................................. 16
3.3 Power saving....................................................................................................... 16
3.4 Bandwidth of logical channels .............................................................................16
4 Structure of the multiplexer protocol........................................................................17
4.1 Introduction of the multiplexer protocol................................................................17
4.2 Data link layer......................................................................................................17
4.2.1 Flag sequence....................................................................................... 18
4.2.2 Address field.......................................................................................... 18
4.2.3 Control field............................................................................................19
4.2.4 Length indicator..................................................................................... 20
4.2.5 Information field..................................................................................... 20
4.2.6 Frame checking sequence field (FCS)...................................................20
4.3 State diagrams.....................................................................................................21
4.3.1 Start-up procedure.................................................................................25
4.3.2 DLC establishment.................................................................................25
4.3.3 Information transfer................................................................................25
4.3.4 DLC release...........................................................................................26
4.3.5 Close-down procedure...........................................................................26
4.3.6 Multiplexer control channel.................................................................... 26
4.3.7 Multiplexer close down (CLD)................................................................27
4.3.8 Test command (Test).............................................................................27
4.3.9 Modem status command (MSC)............................................................ 28
4.3.10 Power saving control (PSC)...................................................................30
4.3.11 Non-supported command response (NSC)............................................31
4.4 Example: Establishing logical channels without parameter negotiation ..............32