this SIM5218 AT command manual - Cooking Hacks

SIM5218 Serial AT Command Set
Supports DNS query,so it may be a string like “www.google.cn.”.
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 identifies the port of local socket, the range of permitted values is 0 to
65535.
A string parameter that displays the cause of occurring error.
Examples
AT+CIPOPEN=0,"TCP","116.228.221.51",100
Connect ok
OK
AT+CIPOPEN=1,"UDP",,,8080
OK
AT+CIPOPEN=
+CIPOPEN: (0-9), ("TCP", "UDP")
OK
AT+CIPOPEN
+CIPOPEN: 0, "TCP", "116.228.221.51", 100
+CIPOPEN: 1
+CIPOPEN: 2
+CIPOPEN: 3
+CIPOPEN: 4
+CIPOPEN: 5
+CIPOPEN: 6
+CIPOPEN: 7
+CIPOPEN: 8
+CIPOPEN: 9
OK
AT+CIPOPEN=0,"TCP","www.google.cn",80
Connect ok
OK
19.22 AT+CIPSEND Send data in multi-client mode
Description
The command sends some data to remote host in mult-client mode.
SIM5218_Serial _ATC_V1.36 380
5/15/2012