Data Sheet

SIM900 AT Commands Set
SIM900R01_ATC_V1.00 86 15.01.2010
ode>[,<subset>[,
<port_speed>[,<
N1>[,<T1>[,<N2
>[,<T2>[,<T3>[,<
k>]]]]]]]]]
Parameters
<mode> multiplexer transparency mechanism
0 Basic option
<subset> the way in which the multiplexer control channel is set up
0 UIH frames used only
<port_speed> transmission rate
1 9 600 bits/t
2 19 200 bits/t
3 38 400 bits/t
4 57 600 bits/t
5 115 200bit/s
6 230 400 bits/t
7 460 800 bits/t
Proprietary values, available if MUX NEW PORT
SPEED FTR is activated
8 921 600 bits/t
Proprietary values, available if MUX NEW PORT
SPEED FTR is activated
<N1> maximum frame size
1-32768 Default: 31 (64 if Advanced option is used)
<T1> acknowledgement timer in units of ten milliseconds
1-255 Default:10(100 ms)
<N2> maximum number of re-transmissions
0-100 Default:3
<T2> response timer for the multiplexer control channel in units of
ten milliseconds
2-255 Default:30
<T3> wake up response timers in seconds
1-255 Default:10
<k> window size, for Advanced operation with Error Recovery
options
1-7 Default:2
Read Command
AT+CMUX ?
Response:
+CMUX:[<mode>[,<subset>[,<port_speed>[,<N1>[,<T1>[,<N2>[,<T2
>[,<T3>[,<k>]]]]]]]]]
OK
ERROR
Reference
GSM 07.07 [13]
Note
z The multiplexing transmission rate is according to the current serial
baud rate. It is recommended to enable multiplexing protocol under