Specifications

AT Command Set
TC35-ATC-01-V02.10 Page 67/145 02.10 / 23.05.2001
4.24 AT+CMUX Enter multiplex mode
Test command
AT+CMUX=?
This command is used to start the multiplexing protocol control channel,
as described in detail in ETSI standard GSM 07.10 (See download area at
„www.etsi.org“. The document can be obtained free-of-charge,
however, a registration procedure may be necessary.).
Supplied by Siemens AG additional customer information regarding the
implementation of multiplex mode is available, see document „Multiple-
xer Protocol GSM 07.10 for GSM-Engine TC37“.
The GSM 07.10 multiplexer protocol operates between the MS and a TE
and allows a number of simultaneous sessions over one normal serial
asynchronous interface. Each session consists of a stream of bytes
transferring various kinds of data; for instance, voice, fax, data, SMS,
phonebook maintenance, battery status etc.
This permits, for example, SMS to be transferred to a TE when a data
connection is in progress. Many other combinations are possible. The
multiplexer allows a complete system to be partitioned in a flexible way
between a MS and TE.
Response
+CMUX: (list of supported <mode>s) OK
Read command
AT+CMUX?
Response
+CMUX: <mode> OK
If error is related to ME functionality:
+CME ERROR: <err>
Write command
AT+CMUX=<mode>
Response
OK
If error is related to ME functionality:
+CME ERROR: <err>
Parameter
<mode> multiplexer transparency mechanism
0 basic option
Note: Subparameters defined in GSM07.07 are adjusted for control and
logical channels as follows:
<subset> 0 UIH frames used only (control channel)
Reference
GSM 07.07
Note
1. This command is used to enter the multiplex mode. The establish-
ment of any logical channel has to be initiated by the TE, thus it acts
always as the initiator. Therefore the TE has to ensure that logical
channels are established before any further actions on them can be
started.
2. There is a timeout of five seconds, if the multiplexer protocol is en-
abled and no multiplexer control channel is established. The TC35
goes back to at-command mode.
3. '+++' is not available in multiplex mode.