At+Cmux Multiplexer Control - Quectel M35 Command Manual

 The command "A/" can‟t be used.
 Only the string "AT" or "at" can be detected (either "AT" or "at").
 URCs that may be issued before the TA detects a new baud rate by receiving the first AT
character, and they will be sent at the previously detected baud rate.
 If TE‟s baud rate is changed after TA has recognized the earlier baud rate, loss of
synchronization between TE and TA would be encountered and an "AT" or "at" string must be
re-sent by TE to regain synchronization on baud rate. To avoid undefined characters during
baud rate resynchronization and the possible malfunction of resynchronization, it is not
recommended to switch TE‟s baud rate when adaptive baud is enabled. Especially, this
operation is forbidden in data mode.
3. Adaptive baud and baud rate after restarting.
In the adaptive baud mode, the detected baud rate is not saved. Therefore, resynchronization is

required after restarting the module.
 Unless the baud rate is determined, an incoming CSD call can‟t be accepted. This must be taken
into account when adaptive baud and auto-answer mode (ATS0 ≠ 0) are enabled at the same
time, especially if SIM PIN 1 authentication is done automatically and the setting ATS0 ≠ 0 is
stored to the user profile with AT&W.
 Until the baud rate is synchronized, URCs after restarting will not be output when adaptive baud
is enabled.
4. Adaptive baud and multiplex mode.
If adaptive baud is active it is not recommended to switch to multiplex mode.
5. Adaptive baud and Windows modem.
 The baud rate used by Windows modem can be detected while setting up a dial-up GPRS/CSD
connection. However, some Windows modem drivers switch TE‟s baud rate to default value
automatically after the GPRS call is terminated. In order to prevent no response to the Windows
modem when it happens, it is not recommended to establish the dial-up GPRS/CSD connection
in adaptive baud mode.
Based on the same considerations, it is also not recommended to establish the FAX connection

in adaptive baud mode for PC FAX application, such as WinFax.
NOTE
To assure reliable communication and avoid any problem caused by undetermined baud rate between
DCE and DTE, it is strongly recommended to configure a fixed baud rate and save it instead of using
adaptive baud after start-up.

3.7. AT+CMUX Multiplexer Control

AT+CMUX Multiplexer Control
Test Command
AT+CMUX=?
M35_AT_Commands_Manual
Response
+CMUX: (list of supported
Confidential / Released
GSM/GPRS Module
M35 AT Commands Manual
<mode>s), (<subset>s),
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