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Expired Canadian patentCanada

Loop transmission system and method of controlling the loop-back condition thereof

CA 1196976 A · Owner: Fujitsu Limited · Inventors: Tazaki, Kenshi; Aritaka, Norihiro; Takeyama, Akira

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Abstract From the Canadian patent

A loop transmission system and a method of controlling the loop-back condition thereof. The loop transmission system comprises a plurality of node stations, a supervisory station, and two duplicate loop transmission lines which transmit signals in opposite directions. In the loop transmission system the, supervisory station first sends out loop-back commands via both of the duplicate loop transmission lines when faults are detected on both of the duplicate loop transmission lines at the same time. Each of the node stations establishes a loop-back path while retaining a connection path to a succeeding node station upon the receipt of a loop-back command. The loop-back path is released only …

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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

  • Granted November 19, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 19, 2002.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledAugust 17, 1983
GrantedNovember 19, 1985
Term endedNovember 19, 2002
Patent numberCA 1196976 A
Classification (IPC)H04L1/00 +2 more

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedAug 17, 1983Patent grantedNov 19, 1985Term endedNov 19, 2002

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