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Expired Canadian patentCanada

Bimodal portable telephone

CA 2135220 C · Owner: Chang, Yum Cheng · Inventors: Leland, Kenneth White; Fok, Wilson; Chang, Yum Cheng

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 bimodal portable telephone provides cellular service and improved cordless service in a common handset. Operation of the bimodal portable telephone in a cellular telephone system provides telephone service over a wide geographical area of coverage through operation with multiple cellular bases and in a cordless telephone system provides telephone service over a localized geographical area of coverage through operation with an associated cordless base. The cordless service provides improved performance over convention cordless telephone service by advantageously employing a frequency hopping spread spectrum modulation technique for communications between the portable telephone and the …

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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 November 7, 1994 and granted February 16, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 7, 2014.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 7, 2016.
  • 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 7, 1994
GrantedFebruary 16, 1999
Term endedNovember 7, 2014
Patent numberCA 2135220 C
Classification (IPC)H04W88/06 +1 more

Timeline

Timeline From CIPO dates

1995199719992001200320052007200920112013Application filedNov 7, 1994Patent grantedFeb 16, 1999Term endedNov 7, 2014

Sources & verification

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