Adaptive Baud - Quectel M35 Command Manual

57600
115200
NOTES
1. The default configuration of AT+IPR is adaptive baud enabled (AT+IPR=0).
2. If a fixed baud rate is set, make sure that both TE (DTE, usually external processor) and TA (DCE,
Quectel GSM module) are configured to the same rate. If adaptive baud is enabled, the TA could
automatically recognize the baud rate currently used by the TE after receiving "AT" or "at" string.
3. The value of AT+IPR cannot be restored with AT&F and ATZ, but it is still storable with AT&W and
visible in AT&V.
4. In multiplex mode, the baud rate cannot be changed by the write command AT+IPR=<rate>, and the
setting is invalid and not stored even if AT&W is executed after the write command.
5. A selected baud rate takes effect after the write commands are executed and acknowledged by "OK".
Example
AT+IPR=115200
OK
AT&W
OK
AT+IPR?
+IPR: 115200
OK
3.6.1.

Adaptive Baud

To take advantage of adaptive baud mode, specific attention must be paid to the following requirements:
1. Adaptive baud synchronization between TE and TA.
 Ensure that TE and TA are correctly synchronized and the baud rate used by the TE is detected
by the TA. To allow the baud rate to be synchronized simply use an "AT" or "at" string. This is
necessary after customer activates adaptive baud or when customer starts up the module with
adaptive baud enabled.
 It is recommended to wait for 2 to 3 seconds before sending the first "AT" or "at" string after the
module is started up with adaptive baud enabled. Otherwise undefined characters might be
returned.
2. Restriction on adaptive baud operation.
 The serial interface shall be used with 8 data bits, no parity and 1 stop bit (factory setting).
M35_AT_Commands_Manual
// Set fixed baud rate to 115200
// Store current setting, that is, the serial
communication speed is 115200 after restart
module
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