Trunk Group Busy RAD gives Mitel IP telephone users recorded messages when all trunks in a trunk group are busy on an outgoing call attempt. This feature is useful for private network applications.
When a user dials an external number, the system selects an outgoing trunk group. If all trunks in the group are busy, the system saves the dialed digits (number) and gives the caller the trunk group busy message. When the RAD message timer expires the caller is camped-on to the trunk group and then is switched to music. When a trunk group becomes available the system seizes the trunk and outpulses the dialed digits.