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SIM7500_SIM7600_SIM7800 Series_MQTT_AT Command Manual 22 / 41
<client_index>
A numeric parameter that identifies a client. The range of permitted
values is 0 to 1.
<req_length>
The length of input topic data. The publish message topic should be
UTF-encoded string. The range is from 1 to 1024 bytes.
<qos>
The publish message’s qos. The range is from 0 to 2.
0 – at most once
1 – at least once
2 – exactly once
The result code: 0 is success. Other values are failure. Please refer
to chapter 2.3.1.
2.2.14 AT+CMQTTSUB Subscribe a message to server
AT+CMQTTSUB is used to subscribe a message to MQTT server.
NOTE: The topic will be clean after execute AT+CMQTTSUB.
AT+CMQTTSUB Subscribe a message to server
Test Command
AT+CMQTTSUB=?
Response
+CMQTTSUB (0-1),(0-1024),(0-2),(0-1)
OK
Write Command
/* subscribe one or more topics which input
by AT+CMQTTSUBTOPIC*/
AT+CMQTTSUB=<client_index>[,<dup>
]
Response
a)If successfully:
OK
+CMQTTSUB: <client_index>,0
b)If failed:
OK
+CMQTTSUB: <client_index>,<err>
c)If failed:
+CMQTTSUB: <client_index>,<err>
ERROR
d)If failed:
Write Command
/* subcribe one topic*/
AT+CMQTTSUB=<client_index>,<reqLe
ngth>,<qos>[,<dup>]
a)If successfully:
>
<input data here>