Abstract: A system that provides video signal communication between a source of video signals and a plurality of units that include destinations of the video signals, the system including an interface coupled to the source and to conductive paths, each of which serves at least one of the units and carries voice signals to and from one or more telephone devices at said unit. The interface receives video signals from the source, and also receives voice signals. The interface transmits voice and video signals onto the conductive path. Receivers at each destination of information connected to the conductive path recover the video signal and apply it to one or more of the destinations at the unit. The receivers also recover the voice signal from the telephone line and apply it to a telephone device. Signals also transmit in the reverse direction, from the units back to the interface and the source of information.

Abstract: An audio/video transmission system for facilitating transmission of video, hi-fi audio, digital, and control signals (such as infrared remote control signals) between different locations in a residence using existing and active telephone wiring. Simultaneous transmission of signals of each type over active telephone lines is achieved without interference with telephone communications or with the other signal types. Transmission succeeds without requiring special treatment of the video signals beyond RF conversion, despite signal attenuation inherent in transmission over the telephone line media. The fidelity of audio reproduction at the receiving locations is sufficiently high to support the transmission of signals from digital devices without significant loss of audio quality. Multiple video sources and high fidelity audio sources may be tied into the system and selected as desired.

Abstract: A high speed switching circuit is disclosed in which two cascode circuits are coupled and operated in push-pull operation. The cascode circuits are clamped to avoid slowing down of the transistors due to saturation.