> 4.10 | AT+CMUX Enter multiplex mode

> All information provided in this section applies to the ASC0 interface only. The second interface ASC1 has no support of Multiplex mode.
> Multiplex mode according to GSM 07.10 and 3G TS 27.010 enables one serial asynchronous interface to be partitioned into three virtual channels. This allows you to take advantage of up to 3 simultaneous sessions running on one interface. For example, you can send or receive data or make a call on the first channel, while the other two channels are free to control the module with AT commands.
> The TC65 module incorporates an internal multiplexer and thus integrates all the functions needed to implement full-featured multiplex solutions. For the application on top, customers have the flexibility to create their own multiplex programs conforming to the multiplexer protocol. To help system integrators save the time and expense of designing multiplexer applications, SIEMENS AG offers WinMUX2k, a ready-to-use multiplex driver for Windows 2000 and Windows XP. Another approach is to develop customized solutions based on the sources of the WinMux2k driver.
> Refer to [7] which provides a detailed description of the multiplex architecture and step-by-step instructions of how to install and configure the multiplex mode. The WinMUX2k driver and its source files can be supplied on request. Please contact your local distributor to obtain the latest installation software and user's guide.
> Syntax

> Test Command AT+CMUX=?
> Response(s)
> +CMUX: (list of supported<mode>s)
> OK

> Read Command AT+CMUX?
> Response(s)
> +CMUX: <mode>
> OK
> ERROR
> +CME ERROR: <err>

> Write Command AT+CMUX=<mode>
> Response(s)
> OK
> ERROR
> +CME ERROR: <err>

> Reference(s) |  | PIN |  | ASC0 | ASC1 | USB | MUX1 | MUX2 | MUX3 |  |  | Charge | Q | Last
> GSM 07.07, GSM 07.10 |  | - |  | + | - | + | - | - | - |  |  | - | + | +

> Parameter Description

> <mode>(num)

> Multiplexer transparency mechanism
> 0
> Basic option

> <subset>(num)

> Subparameters defined in GSM07.07 are adjusted for control and logical channels as follows
> 0
> UIH frames used only (control channel)
> Notes

> • | 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.

> • | There is a timeout of five seconds, if the multiplexer protocol is enabled and no multiplexer control channel is established. The GSM engine returns to AT command mode.

> • | The parameter maximum frame size (N1) of AT+CMUX in GSM 07.10 is set to 98 bytes by default. All other parameters are not available. See [7] for further details on the frame size.

> • | The Multiplex feature is not relevant for Java applications. The mode cannot be started if the ME is Java controlled. If Java autostart is enabled with AT^SCFG, it is not possible to activate Multiplex mode on ASC0 or USB.

> • | Multiplexer mode requires character framing to be set to 8 bits, no parity and 1 stop bit. The setting can be made using (AT+ICF=3).