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Automatic device for testing telephone equipment

  • US 3,875,343 A
  • Filed: 03/19/1973
  • Issued: 04/01/1975
  • Est. Priority Date: 03/21/1972
  • Status: Expired due to Term
First Claim
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1. An automatic telephone line test device comprising detector means for detecting intervals of telephone ringing current appearing on said line, generating means for generating signals at audio frequency, first relay means connected to have one position to connect the detector means to a telephone line and another position to connect the generator means to said telephone line, multi-stage ringing interval counter means for counting a predetermined number of ringing current intervals as they are received over said line and detected by the detector means, timing circuit means operating during a predetermined interval of time and resetting said ringing interval counter means to an initial state at the end of said time interval, control means actuated by an output of said ringing interval counter means to switch said electromagnetic relay to said other position to trigger the operation of the said timing circuit means.

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