The present invention describes a system and method for communicating voice and data over a packet-switched network that is adapted to coexist and communicate with a legacy PSTN. The system permits packet switching of voice calls and data calls through a data network from and to any of a LEC, a customer...http://www.google.com/patents/US8085761?utm_source=gb-gplus-sharePatent US8085761 - Voice over data telecommunications network architecture
