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Expired Canadian patentCanada

Communications transmission system including facilities for suppressing electromagnetic interference

CA 2036662 C · Owner: Parks, Kenneth B. · Inventors: Friesen, Harold Wayne; Adriaenssens, Luc W.; Nutt, Wendell Glenn

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

A balanced mode transmission system (20) for use in a local area network includes at least one twisted pair of insulated metallic conductors (27-27) which at its end is connected through a transformer to a transmitting computer and to a receiving computer (48). Each pair adjacent to the transmitting end and optionally to the receiving end is provided with a longitudinal choke (56,57). Also a, longitudinally extending metallic wire (60) is included in the system and is connected possibly through a resistor to ground at each end. The combination of the longitudinal choke at least adjacent to the transmitting end and the longitudinally extending metallic wire is superbly effective in …

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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 February 19, 1991 and granted February 3, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 19, 2011.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 19, 2013.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledFebruary 19, 1991
GrantedFebruary 3, 1998
Term endedFebruary 19, 2011
Patent numberCA 2036662 C
Classification (IPC)H01B11/06 +2 more

Timeline

Timeline From CIPO dates

1992199419961998200020022004200620082010Application filedFeb 19, 1991Patent grantedFeb 3, 1998Term endedFeb 19, 2011

Sources & verification

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