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Busy/no-answer call completion equipment

  • US 4,935,958 A
  • Filed: 12/19/1988
  • Issued: 06/19/1990
  • Est. Priority Date: 09/22/1986
  • Status: Expired due to Term
First Claim
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1. Apparatus for recognizing a telephone call supervision signal by comparing its frequency and cadence to the frequency and cadence of at least one learned call supervision signal, comprising:

  • a detector for receiving a first call supervision signal and outputting frequency parameters which indicate whether predetermined standard frequencies are present in the received signal;

    a processor coupled to said detector for determining the first call supervision signal cadence and outputting a corresponding cadence parameter;

    a memory for storing the frequency and cadence parameters for at least one call supervision signal;

    means for selectively transmitting said cadence and frequency parameters of said first call supervision signal to said memory based on whether said first call supervision signal is to be learned;

    said detector operable to receive a second call supervision signal and output a frequency parameter in response, said processor operable to determine the cadence of said second call supervision signal and output a cadence parameter in response; and

    recognition circuits operable to compare the frequency and cadence parameters of said second signal with said frequency and cadence parameters of said first call supervision signal stored in memory.

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