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Method and apparatus for providing answer supervision and an autonomous pay telephone incorporating the same

  • US 5,134,651 A
  • Filed: 04/18/1991
  • Issued: 07/28/1992
  • Est. Priority Date: 04/18/1991
  • Status: Expired due to Fees
First Claim
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1. A method for providing call answer supervision to determine if a call placed to a given telephone number has been answered by a called party at the given telephone number, the method comprising the steps of:

  • transmitting a tone of a given frequency on a transmit line of a telephone;

    monitoring a receive line of the telephone to determine if the tone is received back on the receive line;

    simultaneously monitoring the transmit and receive lines to determine the presence of other audio activity; and

    determining that the placed call has been answered if at least one of the following conditions occurs;

    1) the tone of the given frequency is received back on the receive line; and

    2) audio activity having a non-repetitive cadence is present on both the transmit and receive lines of the telephone.

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