In a communications network, voice and facsimile calls are established between first and second and second terminals via first and second media gateways in a communications network. Each gateway is capable of autonomous transitioning between a voice over IP (VoIP) call mode and a facsimile over IP (FoIP)...http://www.google.de/patents/US7907708?utm_source=gb-gplus-sharePatent US7907708 - Voice and fax over IP call establishment in a communications network
