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System for monitoring dialled telephone numbers

  • US 4,013,839 A
  • Filed: 11/08/1974
  • Issued: 03/22/1977
  • Est. Priority Date: 09/10/1974
  • Status: Expired due to Term
First Claim
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1. A system for monitoring numbers dialled over a telephone line the system comprising at least one recording means for sensing dial pulses representative of numbers dialled as well as pulses bearing no relationship to to said numbers dialled on a monitored telephone line and for recording each of the sensed pulses on a recording medium, and processing means for playing-back the recorded pulses on the recording medium, for analysing the pulses recorded thereon to determine the numbers dialled on the monitored line and for producing a display of numbers dialled.

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