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Expired Canadian patentCanada

Conference circuit for pulse coded modulated telephony

CA 1081831 A · Owner: Gte Automatic Electric Laboratories Incorporated · Inventors: Mclaughlin, Donald W.; Lee, David Q.

CIPO record

Overview

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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 method of providing a multi-port conference circuit for use in a telephone switching system employing pulse coded modulated signals for transmission and supervision. Samplings of coded information are employed as a source of conference data and comparison with the digital information contained therein is employed to choose the speaker in a conference group. Included circuitry provides compensation for degradation caused by speech clipping and noise.

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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 July 15, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 15, 1997.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledSeptember 1, 1977
GrantedJuly 15, 1980
Term endedJuly 15, 1997
Patent numberCA 1081831 A
Classification (IPC)H04M3/56 +1 more

Timeline

Timeline From CIPO dates

1978198019821984198619881990199219941996Application filedSep 1, 1977Patent grantedJuly 15, 1980Term endedJuly 15, 1997

Sources & verification

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