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Expired Canadian patentCanada

Line protection switching system

CA 1067986 A · Owner: Western Electric Company, Incorporated · Inventors: Mitchell, William J. (Jr.); Fang, Geng-Seng

CIPO record

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

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Abstract From the Canadian patent

Abstract of the Disclosure Protection for service lines linking offices in a communications sytem is realized by linking the offices in a sequence with a serial connection of protection lines. Protection for service lines which bypass one or more of the offices in the serial sequence is achieved by automatically controllably cascading appropriate ones of the protection lines. The cascading of protection lines is realized on a nonhierarchical basis by assigning each service line in the system a unique address and by supplying a protection switch request message including the address of the requesting service line sequentially to each office in the serial sequence until the transmit-end of …

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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 December 11, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 11, 1996.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Filed—
GrantedDecember 11, 1979
Term endedDecember 11, 1996
Patent numberCA 1067986 A
Classification (IPC)H04Q3/58 +1 more

Timeline

Timeline From CIPO dates

198019821984198619881990199219941996Patent grantedDec 11, 1979Term endedDec 11, 1996

Sources & verification

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