5.6
Baud Rate
GR/GS64 supports baud rates ranging from 9600 to 230400. They correspond to the
third parameter of the AT+CMUX command.
If autobaud is active (i.e. AT+IPR=0) when the MUX is started, it is automatically
turned off and the MUX continues to operate at the baud rate in which the +CMUX
command is entered. For example, if auto baud is active, a host application can switch
baud to 115200 and send AT+CMUX=0,0,5<CR> and SABM on channel 0 at that
baud rate. Once the MUX is closed the module will be placed back into autobaud.
On the other hand, if autobaud is OFF (e.g. AT+IPR=115200), the host application has
to send AT+CMUX=0,0,5<CR> and send SABM at the baud rate of 115200. Sending
them at any other baud rate will fail.
5.7
Flow Control
Two kinds of flow controls are supported by GR/GS64 MUX.
•
Individual channel flow control enabled by MSC
•
Aggregate flow control enabled by the Hardware signals RTS and CTS.
Individual channel flow control is achieved via MSC on the MUX control channel.
Aggregate flow control is achieved by hardware and the hardware handshake signals
are used instead of FCon and FCoff (defined in 27.010 spec) to provide fast response.
Please see section 6.5 - Flow control and Buffer Management for more information.
5.8
Low Power Mode
Autonomous standby mode stays effective in MUX mode if it was enabled (by
AT*E2RS232 command) in serial mode before activation of the MUX mode. Standby-
handshaking on the other hand does not work with MUX because it involves direct
control of RS232 signal lines.
5.9
T3 Timer
After GR/GS64 has received AT+CMUX command, if it does not receive SABM on
channel 0 before the timer T3 expires, it will revert to normal AT mode. Since the MUX
activation usually takes more than 4 seconds for GR/GS64, T3 parameter of the
AT+CMUX command should be greater than 10 seconds.
Gx64 APPLICATION NOTE
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27.010 MUX Feature
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