Multiplexer User's Guide

Confidential / Released

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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

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