Quectel EC25 Command Manual page 137

Write Command
AT+CNMA=<n>
Maximum Response Time
Reference
3GPP TS 27.005
Parameter
<n> Parameter required only for PDU mode
0 Command operates similarly as in text mode
1 Send positive (RP-ACK) acknowledgement to the network. Accepted only in PDU mode
2 Send negative (RP-ERROR) acknowledgement to the network. Accepted only in PDU
mode
NOTE
The Execution and Write Commands shall only be used when AT+CSMS parameter <service> equals 1
(phase 2+) and an appropriate URC has been issued by the module, i.e.:
+CMT for <mt>=2 incoming message classes 0,1,3 and none;
+CMT for <mt>=3 incoming message classes 0 and 3;
+CDS for <ds>=1.
Example
AT+CSMS=1
OK
AT+CNMI=1,2,0,0,0
OK
+CMT: "+8615021012496",,"13/03/18,17:07:21+32",145,4,0,0,"+8613800551500",145,28
This is a test from Quectel.
AT+CNMA
OK
AT+CNMA
+CMS ERROR：340
EC25&EC21_AT_Commands_Manual
ERROR
If there is any error related to ME functionality:
+CMS ERROR: <err>
Response
OK
ERROR
If there is any error related to ME functionality:
+CMS ERROR: <err>
300ms
//Short message is outputted directly when an SMS is incoming.
//Send ACK to the network
//The second time to return error. It needs ACK only once
LTE Module Series
EC25&EC21 AT Commands Manual
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