Siemens Mux_guide_v06 DLC release, Close-down procedure, Multiplexer control channel, Type field

Page 26

Multiplexer User's Guide

Confidential / Released

s

mobile

4.3.4 DLC release

No provision is made to repeat the request if no response is received.

Customer

DISC: P = 1

GSM

µC

engine

 

UA: F = 1

 

DM: F = 1 responding station is

 

already disconnected

Figure 9: DLC release

4.3.5 Close-down procedure

To close down the multiplexer follow these two steps:

First, disconnect all DLCIs by sending the DLCI Release command within the multiplexer control channel frame (as described in section 4.3.6).

Finally, close down the multiplexer control channel (DLCI = 0) by sending the multiplexer close down command CLD (see section 4.3.7). After this, both the “initiating station” and the “responding station” revert to AT command mode.

Before closing the multiplexer make sure that there is no ongoing activity on one of the channels. For example, check that voice, CSD or GPRS connections have ended and wait until all pending AT command responses are received.

4.3.6 Multiplexer control channel

DLCI = 0

Type

Length

Value 1

Value 2

.....

Value n

1 Octet

n Octets

1 Octet

1 Octet

1 Octet

 

Information Field

Figure 10: Multiplexer control channel

The commands are sent as information in the multiplexer control channel frame.

Type field:

Bit 1

Bit 2

Bit 3

Bit 4

Bit 5

Bit 6

Bit 7

Bit 8

 

 

 

 

 

 

 

 

EA

C/R

T1

T2

T3

T4

T5

T6

 

 

 

 

 

 

 

 

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.

 

 

 

 

Mux_guide_v06

Page 26 of 36

30.06.2004

Image 26
Contents Version DocID Muxguidev06 Siemens Cellular EnginesJune 30 Document Name Multiplexer Users GuideMultiplexer Users Guide Muxguidev06Contents Tables Multiplexer protocol version controlChapter What is new Document historyIntroduction Supported products and related documents ReferencesTerm and abbreviations Abbreviation DescriptionMultiplexer protocol an overview Product concept and architectureVirtual channels and AT commands Basic requirements CharacteristicsIntegrating multiplexer into the customer application RestrictionsFunctions without channel dependencies Timing conditions Logical flow control Multiplexer control and signaling linesFlow control RTS/CTS on the physical channelsRTS/CTS on the logical channels COM M COM N COM P RTS/CTSEscape sequence Power savingBandwidth of logical channels Data link layer Structure of the multiplexer protocolIntroduction of the multiplexer protocol Flag sequence Address fieldControl field Frame TypeFrame checking sequence field FCS Length indicatorInformation field BitState diagrams Relationship between the customer µC and the GSM engine µC Serial Interface Customer GSM engine AT+CMUXSerial interface Customer µCGSM engine CustomerEngine ResponderMultiplexer control channel Close-down procedureDLC release Type fieldLength field Test command TestMultiplexer close down CLD Modem status command MSC Break signal optional Bit Not supported Type Bit Power saving control PSCCommands Bit Description Value octet Length=1 BitNon-supported command Non-supported command response NSCValue octet Bit Command Type No Value octet Length=0Customer GSM engine µC AT+CMUXMultiplexer protocol version control IntroductionSignals Bit Modem status command MSCSignals Break Signals Octet Optional Command Bit Multiplexer protocol versionsTroubleshooting Implementing version controlCoding of TestCommand message Example of TestCommand message