At+Cmux Enter Multiplex Mode - Siemens TC37 Module At Command Reference

AT Command Set

4.24 AT+CMUX Enter multiplex mode

TC35 / TC37 and TC35 Terminal support Multiplex mode according to the GSM 07.10 Multiplexer
Protocol and enables one physical serial asynchronous interface to be partitioned into three virtual
channels. This allows you to take advantage of up to 3 simultaneous sessions running on the serial
interface. Each session represents a stream of bytes conveying various data; such as voice, fax,
data, SMS, phonebook information, battery status etc. For example, you can transfer data over one
channel while two further channels are free to control the GSM engine with AT commands. It should
be noted, however, that voice, data or fax calls cannot be established simultaneously, since the
mobile device provides just one air interface to the network.
To make the three virtual interfaces (channels) available, both the GSM engine and the customer
application must contain Mux components which communicate over the Multiplexer Protocol. In the
GSM engine, the Mux/MP software is already incorporated. The customer application should either
integrate the TC35 Mux/MP software or include a Mux/MP program developed by the customer. The
AT+CMUX write command starts the multiplexing protocol control channel.
Refer to [3] which provides to a detailed description of the Multiplex functionality implemented in
TC35 / TC37 and TC35 Terminal and step-by-step instructions of how to install and configure the
MUX mode. The source files of the TC35 Mux/MP software can be supplied on request. Please
contact your local dealer to obtain the latest installation software and user's guide.
Test command
AT+CMUX=?
Read command
AT+CMUX?
Write command
AT+CMUX=<mode>
Reference
GSM 07.07
TC3X_ATC_01_V04.00
Response
+CMUX: (list of supported <mode>s) OK
Response
+CMUX: <mode> OK
If error is related to ME functionality:
+CME ERROR: <err>
Response
OK
If error is related to ME functionality:
+CME ERROR: <err>
Parameter
<mode> multiplexer transparency mechanism
0 basic option
Subparameters defined in GSM07.07 are adjusted for control and logical
channels as follows:
<subset> 0 UIH frames used only (control channel)
Note
1. The write command is used to enter the multiplex mode. The setup of
the logical channels is initiated by the TE, i.e. the TE acts as initiator.
This means that the TE shall ensure that logical channels are
established before any further actions on the channels can be started.
2. There is a timeout of five seconds, if the multiplexer protocol is enabled
and no multiplexer control channel is established. The GSM engine
Page 86 of 204 29.05.2002