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COMMUNICATION SYSTEM

  • US 3,757,225 A
  • Filed: 03/16/1972
  • Issued: 09/04/1973
  • Est. Priority Date: 03/16/1972
  • Status: Expired due to Term
First Claim
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1. A secure subscription communication system for selectively providing at least two substantially simultaneous displays of different program information from a first multiplexed communication signal containing a plurality of different program information signals and a plurality of command signals, said system comprising at least a first and a second display means for displaying said different program information in response to selected program information signals, each display means having a display signal path over which said program information signals are provided, a common display channel having an associated predetermined signal frequency and a common command signal path;

  • a first and a second control means operatively connected to said first and second display means, respectively, via said display signal path; and

    a first condition responsive means operatively connected to said first and second control means via a common communication signal path, said first multiplexed communication signal being provided to said first and second control means via said communication signal path, said first condition responsive means providing said command signals;

    said first and second control means each including an associated first signal separation means for separating said first multiplexed communication signal into said plurality of program information signals and said plurality of command signals, an associated program information selection control signal generating means operatively connected to said associated first signal separating means for providing a program selection control signal in response to an assocIated unique command signal from said first condition responsive means, said program selection control signal generating means associated with said first control means generating a first selection control signal in response to said first control means associated unique command signal, and said program selection control signal generating means associated with said second control means generating a second selection control signal in response to said second control means associated unique command signal, and an associated first signal operating means operatively connected to said associated first signal separating means and said program selection control signal generating means for operating on said plurality of program information signals with said associated program selection control signal for providing one of said selected program information signals to one of said display means at said associated common display signal frequency via said display signal path, said first selection control signal operating on said plurality of program information signals to provide one of at least said two selected program information signals to said first display means for providing one of said substantially simultaneous displays and said second selection control signal operating on said plurality of program information signals to provide said different one of said selected program information signals to said second display means for providing said different one of said substantially simultaneous displays, whereby a plurality of substantially simultaneously transmitted different programs may be selectively displayed on said common display channel.

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