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Video transmission and control system utilizing internal telephone lines

  • US 5,010,399 A
  • Filed: 07/14/1989
  • Issued: 04/23/1991
  • Est. Priority Date: 07/14/1989
  • Status: Expired due to Term
First Claim
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1. A communication system that includes an electronic switching device that provides an interface to a telephone system, a first port ordinarily used for connection of telephone equipment and an apparatus located in a first area, said apparatus supplying a first video signal, a second port ordinarily used for connection of telephone equipment and a television receiver located in a second area, the communication system further including a first two-wire conductive path connecting said first port to said switching device, and a second two-wire conductive path connecting said second port to said switching device, the communication system further including:

  • (a) a first electronic device located in said first area including;

    receiving means connected to said first apparatus, for receiving said first video signal.signal processing means for providing a second video signal, said second video signal having a higher energy level than said first video signal and substantially the same information content as said first video signal, andfirst transmitting means, connected to said first one of said ports, for transmitting said second video signal onto the network, said first transmitting means comprising first filtering means for presenting a high impedance to signals whose energy is concentrated at frequencies below the highest frequency used for communication by ordinary telephone devices, while allowing said second video signal to transmit substantially unaltered;

    (b) a second electronic device located in said second area including;

    recovering means, connected to said second one of said ports, for recovering said second video signal from the network, said recovering means comprising second filtering means for presenting a high impedance to signals whose energy is concentrated at frequencies below the highest frequency used for communication by ordinary telephone devices, while allowing said second video signal to transmit substantially unaltered; and

    second transmitting means, connected to said television receiver, for transmitting said video signals to said television receiver,(c) a connecting device (52) interposed along said first 2-wire conductive path, including;

    a first low-pass filter for allowing signals at frequencies used by ordinary telephone devices to transmit along said first path unaltered while blocking signals transmitted at frequencies at which the energy of said second video signal is concentrated,said connecting device also being interposed along said second 2-wire conductive path, and including a second low-pass filter for allowing signals at frequencies used by ordinary telephone devices to transmit along said path unaltered while blocking signals transmitted at frequencies at which the energy of said second video signal is concentrated,said connecting device further including a third conductive path connecting said first conductive path and said second conductive path, and including a high pass filter for blocking passage of signals concentrated at frequencies used by ordinary telephone devices, and enabling electrical energy of said second video signal to pass substantially unaltered, for allowing transmission of said second video signal from said first port to said second port, while maintaining the separation of telephone communications signals between said switching device and each of said first port and said second port.

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