Call Forward Reminder Ring

The device supports the Call Forward Reminder Ring feature for FXS interfaces whereby the device's FXS endpoint emits a short ring burst when a third-party Application server (e.g., softswitch) forwards an incoming call to another destination. The ring is emitted only when the endpoint is in on-hook state.

The feature is useful in that it notifies the endpoint user that a call forwarding service is currently being performed. The device generates a call forward reminder ring burst to the endpoint upon receipt of a SIP NOTIFY message containing a "reminder ring" xml body. The NOTIFY message is sent by the Application server to the device each time the server forwards an incoming call. The service is cancelled when the device sends an UNSUBSCRIBE request or when the subscription time expires.

The following procedure describes how to configure the feature.

To configure the call forward reminder ring feature:
1. Open the Supplementary Services Settings page (Setup menu > Signaling & Media tab > Gateway folder > DTMF & Supplementary > Supplementary Services Settings).

2. In the 'Enable NRT Subscription' field (EnableNRTSubscription), select Enable to enable endpoint subscription to ring reminder event notification.
3. In the 'AS Subscribe IP Group ID' field (ASSubscribeIPGroupID), enter the IP Group ID of the Application server providing the services.
4. In the 'NRT Subscribe Retry Time' field (NRTSubscribeRetryTime), enter the retry period (in seconds) for dialog subscription to the Application server if a previous request fails.
5. Configure the reminder ring tone:
a. Configure a tone for the reminder ring in the Call Progress Tone (CPT) file (see Call Progress Tones File).
b. In the 'Call Froward Ring Tone ID' field (CallForwardRingToneID), enter the ID number of the tone that you defined in the previous step.
6. Click Apply.