The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 30, 1994
Filed:
Nov. 04, 1991
Cheng D Yu, Scotch Plains, NJ (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
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.