Quectel EC25 Command Manual page 146

Parameter
<uid> Message identification in the user data header (UDH). Range: 0-65535 (see NOTES).
All segments of a same concatenated message have same <uid>. Different
concatenated messages should have different <uid>.
<msg_seg> Sequence number of a concatenated message. Range: 1-7.
<msg_total> The total number of the segments of one concatenated message. Range: 2-7.
Other parameters please refer to AT+CMGR
NOTES
1. The <uid> in AT+QCMGR is different from the <uid> in AT+QCMGS. It is possible that UE receives
concatenated messages with 8-bit or 16-bit <uid>. So its maximal value is 255 with 8-bit and 65535
with 16-bit.
2. If the message to be read is not a concatenated message, <uid>, <msg_seg> and <msg_total>
would not be shown in the result.
Example
+CMTI: "SM",3
+CMTI: "SM",4
AT+QCMGR= 3
+QCMGR: "REC UNREAD","+8615056913384",,"13/07/30,14:44:37+32",120,1,2
ABCD
OK
AT+QCMGR= 4
+QCMGR: "REC UNREAD","+8615056913384",,"13/07/30,14:44:37+32",120,2,2
EFGH
OK
EC25&EC21_AT_Commands_Manual
//The first message of a concatenated message comes
//The second message of a concatenated message comes
//Read the first segment of the concatenated message
//Read the second segment of the concatenated message
LTE Module Series
EC25&EC21 AT Commands Manual
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