Expired Canadian patentCanada
Tone detector control circuit
CA 920672 A · Owner: Gte Automatic Electric Laboratories Incorporated · Inventors: Vernon F. Weber
Overview
Drawings and full text
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordRead the whole patent
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 February 6, 1973. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 6, 1990.
- 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—
GrantedFebruary 6, 1973
Term endedFebruary 6, 1990
Patent numberCA 920672 A
Classification (IPC)H04Q1/44 +1 more
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.