At&t Bell Laboratories

Cheng D Yu

Andreas Constantine Papanicolaou

Nuri Ruhi Dagdeviren

Khashayar Mohammadi

Walter Patrick Binns

Deirdre T Ryan

A system and method for providing two-way video telephony between an originating location and a destination location, each equipped with an audio/video display (television) and an audio/video source (camera) using available channels dedicated for video telephony on one or more coaxial cable distribution networks which can be part of existing cable television systems. Each location is equipped with a network interface unit (NIU) which modulates outgoing audio/video information (which can be in analog or digital form) together with outgoing control messages onto an attached coaxial cable network. The NIU also demodulates incoming audio/video information and incoming control messages received from the attached coaxial network. Upstream signals may be transmitted to a cable network head end and then to the head end serving the destination location using demodulators, A/D converters (if not already in digital form), multiplexers, and the switched digital telecommunications network. If an intra-cable system call is involved, certain processing steps may be eliminated. Users of the system contend for available channels on the cable distribution network, and channel assignments are made on a per call basis, only for the duration of the call.

Bidirectional video telephony using shared channels on coaxial cable

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 premises. Each of the head ends is connected to a 'point of presence' of a telephone interexchange carrier so that a connection between pairs of head ends, and thus between a pair of video telephone locations, can be made via a switched digital network maintained by the carrier. Certain of originating and destination locations comprise a standard television set, serving as the audio/video display, and a consumer-type camera or camcorder, serving as the audio/video source. Others of the originating and destination locations comprise ISDN video telephones which are connected to the various points of presence of the interexchange carrier via local exchange carrier telephone networks. The video telephone number for cable subscriber locations are administered to be the same as the standard ten-(i.e., area code plus seven-) digit telephone number used for regular telephone calls directed to those locations.

Bidirectional video telephony between cable television and switched

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 premises. Each of the head ends is connected to a 'point of presence' of a telephone interexchange carrier so that a connection between pairs of head ends, and thus between a pair of video telephone locations, can be made via a switched digital network maintained by the carrier. Certain of originating and destination locations comprise a standard television set, serving as the audio/video display, and a consumer-type camera or camcorder, serving as the audio/video source. Others of the originating and destination locations comprise ISDN video telephones which are connected to the various points of presence of the interexchange carrier via local exchange carrier telephone networks. The video telephone numbers for cable subscriber locations are administered to be the same as the standard ten- (i.e., area code plus seven-) digit telephone numbers used for regular telephone calls directed to those locations.

Growing community of inventors

Scotch Plains, NJ, United States of America

Cheng D Yu