Specifications

SIM900 AT Commands Set
SIM900_ATC_V1.01 175 23.06.2010
AT+CIPCLOSE only close connection at the status of TCP/UDP
CONNECTING or CONNECT OK, otherwise response ERROR, after
closing the connection, the status is IP CLOSE when in single IP mode
8.2.7 AT+CIPSHUT Deactivate GPRS PDP Context
AT+CIPSHUT Deactivate GPRS PDP Context
Test Command
AT+CIPSHUT=?
Response
OK
Execution
Command
AT+CIPSHUT
Response
If close successfully:
SHUT OK
If close fail:
ERROR
Reference Note
z If this command executed in multi-connection mode, all of the IP
connection will be shut.
z You can close gprs pdp context by AT+CIPSHUT. After closed, the
status is IP INITIAL.
8.2.8 AT+CLPORT Set Local Port
AT+CLPORT Set Local Port
Test Command
AT+CLPORT=?
Response
+CLPORT: (list of supported <port>s)
OK
Parameters
See Write Command
Read Command
AT+CLPORT?
Response
TCP: <port>
UDP: <port>
OK
Parameters
See Write Command
Write Command
AT+CLPORT=<
mode>,<port>
Response
OK
ERROR
Parameters
<mode> a string parameter(string should be included in quotation
marks) which indicates the connection type
“TCP” TCP local port
“UDP” UDP local port