Patent ID: 7010112

Claim:
A method of managing a trunk to provide a ring-back sound in a subscriber-based ring-back sound service, the ring-back sound service method including the steps of a) a home location register providing first information indicating whether a ring-back tone preset in the home location register is substituted and second information for performing routing to intelligent peripheral means to a corresponding terminating mobile switching center when a location of a terminating subscriber is registered; b) the terminating mobile switching center providing a ring-back tone to an arbitrary originator or requesting a connection of a trunk call from the intelligent peripheral means according to the first and second information, when the terminating mobile switching center recognizes a call connection request transmitted from the arbitrary originator to the terminating subscriber, c) the intelligent peripheral means searching for a ring-back sound preset with respect to the terminating subscriber after connecting the trunk call in response to the trunk call connection request, and providing the searched ring-back sound to the originator instead of the ring-back tone through the trunk-connected terminating mobile switching center, the trunk management method comprises the steps of: The terminating mobile switching center requesting a release of the connected trunk call from the intelligent peripheral means when an answer of the terminating subscriber is recognized or when a first predetermined period of time has elapsed from a time when it is recognized that the searched ring-back sound is provided to the originator; and The intelligent peripheral means requesting a release of the connected trunk call from the terminating mobile switching center when a second predetermined period of time has elapsed from a time when the ring-back sound begins to be provided.