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Push button phone capable of sending to the telephone line alphabetical characters

  • US 4,918,721 A
  • Filed: 08/24/1988
  • Issued: 04/17/1990
  • Est. Priority Date: 08/24/1987
  • Status: Expired due to Term
First Claim
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1. A terminal apparatus for receiving upper and lower case alphabetical characters and being coupled to telephone lines and to a pushbutton telephone having numerical keys used to represent alphabetical characters and special keys used to represent control characters and being capable of communicating on said lines upper and lower case alphabetical characters in the form of DTMF signals, said terminal apparatus comprising:

  • receiving means for receiving said DTMF signals;

    decoding means responsive to said receiving means for decoding the DTMF signals corresponding to predetermined combinations of said keys being pressed; and

    controller means responsive to said decoded signals corresponding to a combination of at least one particular control character and a particular alphabetical character received in succession by said decoding means to generate an output electrical signal indicative of said particular alphabetical character in upper case or lower case.

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