Multiplexer User's Guide
Confidential / Released
4.3.4 DLC release
No provision is made to repeat the request if no response is received.
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
The commands are sent as information in the multiplexer control channel frame.
In the last octet of the sequence the EA bit = 1, otherwise = 0.
If there is only on octet, EA bit = 1 is set.
Indicates whether the sequence is a command or a response.
Coding of the command type.
DISC: P = 1
UA: F = 1
DM: F = 1
responding station is
Figure 9: DLC release
Figure 10: Multiplexer control channel
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