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Expired Canadian patentCanada

Automatic loss control circuit for digital loop transmission system

CA 2065474 C · Owner: Haughton, Lance Junior · Inventors: Yon, Inchol; Haughton, Lance Junior

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A circuit is proposed for adjusting the loss provided to loops in digital loop carrier transmission systems. A constant current is supplied to the loop and the resulting voltage is measured to determine the resistance of the loop. This value is fed to a microprocessor with a look-up table which controls a programmable analog/digital converter. The loss at the output of the converter is a stepwise function based on the resistance of the customer loop.

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Filed April 7, 1992 and granted August 11, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 7, 2012.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 7, 2014.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 7, 1992
GrantedAugust 11, 1998
Term endedApril 7, 2012
Patent numberCA 2065474 C
Classification (IPC)H04L1/00 +2 more

Timeline

Timeline From CIPO dates

1993199519971999200120032005200720092011Application filedApril 7, 1992Patent grantedAug 11, 1998Term endedApril 7, 2012

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.