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Message delivery system operable in an override mode upon reception of a command signal

  • US 4,887,152 A
  • Filed: 01/26/1988
  • Issued: 12/12/1989
  • Est. Priority Date: 01/30/1987
  • Status: Expired due to Term
First Claim
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1. A message delivery system, comprising:

  • (a) a head end apparatus comprising means for reproducing video programs, means for reproducing audio programs, means for reproducing messages, controller means having key means for generating a command signal for said messages, modulator means for modulating said video programs, said messages, and said audio programs and said command signal in different frequency bands, respectively, and multiplexer means for multiplexing said modulated video programs, said modulated messages, said modulated audio programs and said modulated command signal;

    (b) a plurality of terminal units each comprising a means for selecting desired ones of said multiplexed, modulated video programs and audio programs, tuner means coupled to the selecting means for receiving and demodulating said modulated messages, said selected modulated video programs, said selected modulated audio programs, and said modulated command signal, a means for receiving the demodulated command signal and generating in response to the demodulated command signal an override signal for forcing the tuner means to select the frequency band of said modulated messages, a display means for displaying the demodulated selected video programs, an audio output terminal for receiving the demodulated selected audio programs, and a volume control for controlling the amplitude of the demodulated selected audio programs received by the audio output terminal; and

    (c) means for transmitting said video programs, said messages, said audio programs and said command signal from said head end apparatus to the terminal units.

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