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Apparatus for drawing and processing electrical power from a communications line

  • US 5,608,792 A
  • Filed: 05/31/1994
  • Issued: 03/04/1997
  • Est. Priority Date: 04/13/1994
  • Status: Expired due to Term
First Claim
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1. Apparatus for drawing and processing electrical power from a telephone line, the apparatus comprising:

  • a pair of terminals for connection to the telephone line,a signal detector coupled to the terminals;

    a DC to DC converter connected to receive power from the terminals and to power the signal detector for detecting the presence of a predetermined activation signal on the telephone line,the converter comprising an oscillator and a transformer with primary and secondary windings,the oscillator having an output connected to a primary winding of the transformer and causing DC level switching thereto such that power transfer from the telephone line to a secondary winding of the transformer occurs, andthe signal detector, on detection of the activation signal, causing an increase in oscillator frequency to cause an increase in the power transferred.

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