Data Sheet

SIM900 AT Commands Set
SIM900R01_ATC_V1.00 78 15.01.2010
Read Command
AT+CREG?
Response
TA returns the status of result code presentation and an integer <stat>
which shows whether the network has currently indicated the registration
of the ME. Location information elements <lac> and <ci> are returned
only when <n>=2 and ME is registered in the network.
+CREG: <n>,<stat>[,<lac>,<ci>]
OK
If error is related to ME functionality:
+CME ERROR: <err>
Response
TA controls the presentation of an unsolicited result code +CREG: <stat>
when <n>=1 and there is a change in the ME network registration status.
OK
Parameters
<n> 0 disable network registration unsolicited result code
1 enable network registration unsolicited result code
+CREG: <stat>
2 enable network registration unsolicited result code with
location information +CREG: <stat>[,<lac>,<ci>]
<stat> 0 not registered, MT is not currently searching a new
operator to register to
1 registered, home network
2 not registered, but MT is currently searching a new
operator to register to
3 registration denied
4 unknown
5 registered, roaming
<lac> string type(string should be included in quotation marks);
two byte location area code in hexadecimal format
< ci > string type(string should be included in quotation marks);
two byte cell ID in hexadecimal format
Write Command
AT+CREG=<n>
Unsolicited result code
If <n>=1 and there is a change in the MT network registration status
+CREG: <stat>
If <n>=2 and there is a change in the MT network registration status or a
change of the network cell:
+CREG: <stat>[,<lac>,<ci>]
Parameters
see Write Command
Reference Note