Sunsea AIoT SIMCom SIM800 Series, Application Note

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SIM800 Series_Multiplexer_Application Note_V1.04
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No Step
Data Direction
Hex Comment
TE<——>MS
1
TE requests to establish
DLCI1 using SABM frame
——> F9 07 3F 01 DE F9
MS feeds back UA for
receiving SABM and
accepts to create DLCI 1
<——
F9 07 73 01 15 F9
MS send UIH frame MSC
message
<——
F9 01 EF 09 E3
[note 4]
05
07
[note 5]
0D 9A F9
2
TE requests to establish
DLCI2 using SABM frame
——> F9 0B 3F 01 59 F9
MS feeds back UA for
receiving SABM and
accepts to create DLCI 2
<——
F9 0B 73 01 92 F9
MS send UIH frame MSC
message
<——
F9 01 EF 09 E3 05 0B
0D 9A F9
3
Establishment of DLC 3, 4
are the same as above
4
By now, 4 channels have
come into existence.
Multiplexer can work
normally

Note 1:
This frame is used to response SABM
1) If MS responses DM frame to TE, it means establish DLCI failed.
2) If MS responses UA frame to TE, it means establish DLCI successful.
For SIM800 series, when MS responses UA frame to TE, the frame uses one byte to represent the data
length, such as F9 07 73 01 15 F9.
For SIM900 series, when MS responses UA frame to TE, the frame uses two bytes to represent the
data length, such as F9 03 73 00 00 A4 F9.

Note 2:
The bit means DLCI channel.03 means control channel DLCI 0, 07means logical channel DLCI 1,ob
means logical channel DLCI 2,0F means logical channel DLCI 3,13 means logical channel DLCI 4.

Note 3:
The bit means frame type. 3F means SABM frame, 73 means UA frame, 1F means DM frame, 53
means DISC frame, EF means UIH frame.

Note 4:
The bit means the message that UIH frame carries. E3 means MSC message, 43means PSC
message, 63 means FCoff message, A3 means FCon message, C3 means CLD message.
NOTE