Patent ID: 8825108

Claim:
A telecommunication system for handling a call, the system comprising: a cellular system comprising a mobile switching center (“MSC”) configured to provide cellular service to the dual-mode phone that operates in a cellular mode and in a voice over Internet Protocol (“VoIP”) mode; and a VoIP system in communication with the MSC, the VoIP system comprising a VoIP switch and configured to serve as an interface between the MSC and a public switched telephone network (“PSTN”), such that when a call is received on a public VoIP telephone number for the dual mode phone, the VoIP system is configured to: route the call around the MSC and through the VoIP switch to the dual-mode phone when the dual-mode phone is registered with the VoIP system; and route the call through the MSC to a cellular telephone number associated with the dual-mode phone in the cellular system only if the dual-mode phone has unintentionally lost contact with the VoIP system and is thus not registered with the VoIP system, wherein the dual-mode phone, upon obtaining Internet Protocol (“IP”) access, automatically registers with the VoIP system.