In a personal communication service (PCS) environment, where a call to a personal telephone number may be routed to a sequence of telephone numbers until the call is answered or abandoned, and where it is possible that the destination telephones indicated in the sequence may be disconnected telephones...http://www.google.de/patents/US5706339?utm_source=gb-gplus-sharePatent US5706339 - Technique for use in processing personal telephone calls
