this SIM5218 AT command manual - Cooking Hacks

SIM5218 Serial AT Command Set
Client index overflow
Indicate that input client’s index is out of
range.
Connection disconnected
Indicate that the remote end has closed the
connection.
Socket closed
Indicate that socket is closed.
Network closed Indicate that the write command of
AT+NETCLOSE has excuted successfully.
Network is already closed
Indicate that network has been closed now.
Sending time out
Failed to send TCP or UDP data for timer
expire.
Sending failure for network error
Failed to send data for network error
Open failure for network error
Failed to open network for network error.
Server is already listening
Server is already listening
+NETCLOSE: 1
Network is closed for network error
SIM5218_Serial _ATC_V1.36 397
5/15/2012