The present invention relates to method and apparatus for providing an arbitrary sound chosen by a called subscriber instead of ringback tone to a calling subscriber. In this present invention, if a call is received, a terminating exchanger requests a trunk connection to a sound db server based on the...http://www.google.com/patents/US7171200?utm_source=gb-gplus-sharePatent US7171200 - Method and apparatus for providing subscriber-based ringback tone
