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COMBINATION TELEPHONE AND CALCULATOR

  • US 3,865,994 A
  • Filed: 07/30/1973
  • Issued: 02/11/1975
  • Est. Priority Date: 07/30/1973
  • Status: Expired due to Term
First Claim
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1. In a communications device such as a telephone including a housing, input-output lines, a numeric keyboard providing seven separate outputs as inputs to a dual tone generator to create 12 separate tone pairs, the improvement permitting dual use of the telephone keyboard for tone dialing and as an input to a calculator comprising:

  • an electronic calculator positioned within the telephone housing and including numeric inputs from zero to nine plus function inputs;

    switch means disengaging the seven outputs of the keyboard from the tone generators and providing the seven separate outputs as inputs to a decoding matrix; and

    a decoding matrix for decoding the seven outputs into twelve outputs Representative of the numeric keyboard designations and applying the decoded outputs as inputs to the calculator.

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