In a video telephony system, a coaxial cable network, which is preferably a part of an existing cable television system, provides a local link for the transmission of the video telephone signals between each originating and destination location and a respective "head end" located on the cable company...http://www.google.com/patents/US5329308?utm_source=gb-gplus-sharePatent US5329308 - Bidirectional video telephony between cable television and switched telephone systems
