this SIM5218 AT command manual - Cooking Hacks

SIM5218 Serial AT Command Set
a numeric parameter that identifies the port of TCP server, the range of permitted values is 0 to
65535.
NOTE: When open port as TCP, the port must be the opened TCP port;
When open port as UDP, the port may be any port.
But, for Qualcomm, connecting the port 0 is as an invalid operation.
a numeric parameter that requested number of data bytes to be transmitted.
a numeric parameter that confirmed number of data bytes to be transmitted.
-1 the connection is disconnected.
0 own send buffer or other side’s congestion window are full.
A string parameter that displays the cause of occurring error.
Examples
AT+CIPSEND=0,1
> S
OK
+CIPSEND: 1, 1
Send ok
AT+CIPSEND=1,1,”116.236.221.75”,6775
> S
OK
+CIPSEND: 1, 1
Send ok
AT+CIPSEND=
+CIPSEND: (0-9), (1-1024)
OK
19.23 AT+CIPCLOSE Close connection in Multi-client mode
Description
The command closes a specified connection in multi-client mode.
SIM PIN References
YES Vendor
SIM5218_Serial _ATC_V1.36 382
5/15/2012