Abstract: A communication system enabling transmission of individual subscriber teletext messages, audio and video to individual subscribers and permitting group communications of audio, video, teletext and data information from a single central subscriber location, such as a corporate head office to a plurality of satellite offices, such as field or sales offices of the corporation, is disclosed. A composite signal including the information to be transmitted as well as system wide, individual decoder and group decoder control signals is transmitted. The system-wide control signals include data germane to operation of each of the decoders of this system, including key information needed to decode the composite signal. The system-wide control data is transmitted at a first relatively high frequency. The group decoder information includes information permitting individual groups of decoders to receive information portion of the composite signal being transmitted at a given time.
Type:
Grant
Filed:
August 14, 1986
Date of Patent:
September 12, 1989
Assignee:
Scientific Atlanta, Inc.
Inventors:
Nigel Seth-Smith, Cameron Bates, Samson Lim, William van Rassel, Robert Yoneda, Keith Lucas