Definition of SMS´s text and ringing period
First condition is to define text for "SMS at no answer" (red box on the following picture). You also need to setup time period in seconds. This means for how long a GSM station have to be in ringing mode (blue box on following picture). This time period is counted from the moment BRI gateway gets an ALERTING message.
Calling party identification
There has to be calling party identification in incoming SETUP message to 2N® BRI Gateway (CGN element cannot be empty in the SETUP message).