Sunsea AIoT SIMCom SIM800 Series, Application Note, Page: 20 / 25

SIM800 Series_Multiplexer_Application Note_V1.04
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4 MUX Examples
4.1 Establish Channels
Step 1
：
Launch Multiplexer
No Step
Data
Direction
Hex Comment
TE<——>MS
1
TE launches MS
multiplexer function by
AT command
——>
61 74 2B 63 6D 75
78 3D 30 0D 0D 0A
4F 4B 0D 0A 0D 0A
AT+CMUX=0<CR><LF>
MS feed back response <——
61 74 2B 63 6D 75
78 3D 30 0D 0D 0A
4F 4B 0D 0A 0D 0A
AT+CMUX=0<CR><LF>O
K<CR><LF><CR><LF>
Host need quickly send
the establish DLC0 frame,
otherwise the client will
exit MUX state.
Step 2
：
Establish DLC 0
No Step
Data
Direction
Hex Comment
TE<——>MS
1
TE requests to
Establishes control
channel DLCI 0, using
SABM frame
——> F9 03
[note 2]
3F
[note 3]
01 1C F9
SABM Frame
MS feeds back UA
[note 1]
for receiving SABM and
accepts to create DLCI
0
<
——
F9 03 73 01 D7 F9 UA Frame
Step3
：
Establish DLC 1, 2