Nokia 30 GSM Connectivity Terminal At Command Manual page 70

Text mode:
The +CMGL command returns the messages with the status value <stat> from a message
storage to the TE. If the status of the message is 'received unread', the status in the storage
changes to 'received read'.
NOTE: If the selected <mem1> can contain different types of SMs (e.g. SMS-DELIVERs,
SMS-SUBMITs, SMS-STATUS-REPORTs and SMS-COMMANDs), the response may be a
mix of the responses of the different SM types. The TE application can recognise the
response format by examining the third response parameter.
The test command should give a list of all the supported status values.
PDU mode:
The +CMGL command returns messages with the status value <stat> from the preferred
message storage <mem1> to the TE. Entire data units <pdu> are returned. If the status of
the message is 'received unread', the status in the storage changes to 'received read'.
Defined values
<stat> Integer type in the PDU mode (default 0), or string type in the text mode
indicates the status of the message in the memory:
0
1
2
3
4
<index> Integer type value in the range of location numbers
<oa/da> GSM 03.40 TP-Originating/Destination-Address Address-Value field in string
format; type of address given by <tooda/toda>
<scts> GSM 03.40 TP-Service-Centre-Time-Stamp in time-string format
<tooa/toda>/<tora>
octet in integer format
129
145
<length> Integer type value that indicates the length of the message body
<data> In characters in the text mode (+CMGF=1); or integer type value that indicates
the length of the actual TP data unit in octets (i.e. the RP layer, SMSC address
octets are not counted in the length) in the PDU mode (+CMGF=0),
<data> SMS: GSM 03.40 TP-User-Data in the text mode responses
"REC UNREAD" received unread message (i.e. new message)
"REC READ" received read message
"STO UNSENT" stored unsent message (only applicable to SMs)
"STO SENT" stored sent message (only applicable to SMs)
"ALL" all messages (only applicable to the +CMGL command)
GSM 04.11 TP-Originating/Destination-Address Type-of-Address
unknown/telephony
internal/telephony
63/107