Specifications

SIM900 AT Commands Set
SIM900_ATC_V1.01 200 23.06.2010
Activate CID 1, if the CID is already
active, the mobile returns OK at once.
If no CID is defined the mobile
responses +CME ERROR: invalid index.
Note: If the mobile is NOT attached
by AT+CGATT=1 before activating, the
attach is automatically done by the
AT+CGACT Command.
AT+CGACT=1,1
AT+CGACT=1,3
OK
+CME ERROR: requested
service option not subscribed
Use the defined and activated CID
to get online. The mobile can be
connected using the parameters of
appointed CID or using default
parameter
AT+CGDATA=”PPP”,
1
CONNECT
The mobile supports Layer 2 Protocol (L2P) PPP only.
Note: If the mobile is NOT attached by AT+CGATT=1 and the CID is NOT activated before
connecting, attaching and activating is automatically done by the AT+CGDATA Command.
Some providers require to use an APN to establish a GPRS connection. So if you use the
Microsoft Windows Dial-Up Network and ATD*9… to connect to GPRS you must provide the
context definition as part of the modem definition (Modem
properties/Connection/Advanced…/Extra settings.) As an alternative, you can define and activate
the context in a terminal program (e.g. Microsoft HyperTerminal) and then use the Dial-Up
Network to send only the ATD Command.