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Expired Canadian patentCanada

Time switch with a dual memory structure-type control memory

CA 1293804 C · Owner: Nec Corporation · Inventors: Murata, Hatsuho; Hirata, Hideyuki

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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 time switch with a dual structure-type control memory utilizing a time division time switch. m e switch is equipped with a speech memory unit into which digital signals to be interchanged are temporarily written and, a control memory unit into which addresses to be accessed by the speech memory unit are written. The control memory unit has first and second memories. Each memory has an input/output section connected to a memory controller. The memories are set during hard and soft cycles so that when either one of the memories is set in a hard cycle the other memory is set in a soft cycle. The hard cycle is a speech-control data read-only mode. The soft cycle is a speech-control data …

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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 31, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 31, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJanuary 23, 1987
GrantedDecember 31, 1991
Term endedDecember 31, 2008
Patent numberCA 1293804 C
Classification (IPC)H04Q11/04 +1 more

Timeline

Timeline From CIPO dates

1988199119941997200020032006Application filedJan 23, 1987Patent grantedDec 31, 1991Term endedDec 31, 2008

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