Called party availability announcement in a radio telecommunications

Abstract

A method of announcing to a calling party in an originating system in a radio telecommunications network that a called party in a serving system is not available. The method begins by sending a Routing Request (RoutReq) Invoke message from the originating system to the serving system. The RoutReq Invoke message includes a Transaction Capabilities parameter indicating that the originating system is capable of generating announcements. The serving system then determines that the called party is not available. This is followed by sending a Redirection Request (RedReq) Invoke message from the serving system to the originating system. The RedReq Invoke message includes an Announcement List parameter requesting the originating system to provide an announcement to the calling party, and may include a Preferred Language parameter. The RedReq Invoke message also includes an Allow Transfer to Number parameter if the called party subscribes to services requiring service logic support. Any trunk seized from the originating system to the serving system is then released. Finally, the originating system sends the announcement to the calling party announcing that the called party is not available. If a preferred language parameter was received, the originating system makes the announcement in the preferred language indicated.