Are you trying to establish a GPRS data call or a normal voice call?
If you are giving ATD /, this will not create a GPRS call to the specified IP and the port number. The ATD command is used to establish a GSM data/voice call to the specified number. For instance, if you give ATD; it will be a voice call and ATD will be a data call (note the absence of semi colon here).
To be able to establish a GPRS data call, you first need to define a PDP conetxt and then activate that PDP context. You can activate the PDP context using ATD99**1# command (where the PDP context 1 is activated).
Also, note that when you subscribe to a particular command, it means that you want to provide your own functionality to your command. Here you are subscribing to ATD command. Hence, it means that whenever ATD command is given, your “UserHandler” function will be called.
The third parameter of adl_atCmdSubscribe () API defines which type of command should lead to the execution of the callback function “UserHandler”.
Please refer to ADL user guide for more information on how to use this API.
Open AT Fan.