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Expired Canadian patentCanada

Implied principal busy status indicator for covered calls

CA 1297566 C · Owner: Nalbone, Robert Daniel · Inventors: Nalbone, Robert Daniel

CIPO record

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Abstract From the Canadian patent

Abstract, The subject implied principal busy status indicator provides all covering users with an indication of the busy/idle status of the principal's line on a covered call. This is accomplished by equipping each covering user's telephone station set with a principal busy status indicator for every line appearance on the covering user's telephone station set. When a covered call is diverted from a principal's line to the covering user's telephone station set, the line appearance on which the covered call appears is lighted and the principal busy status indicator associated with the covering user's line appearance indicates the busy/idle status of the principal's line. The business …

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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 March 17, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 17, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 24, 1987
GrantedMarch 17, 1992
Term endedMarch 17, 2009
Patent numberCA 1297566 C
Classification (IPC)H04M3/54 +2 more

Timeline

Timeline From CIPO dates

19881991199419972000200320062009Application filedNov 24, 1987Patent grantedMarch 17, 1992Term endedMarch 17, 2009

Sources & verification

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