Pushbutton telephone system
CA 2114039 C · Owner: Hayashi, Hiroaki · Inventors: Aoki, Takashi; Hayashi, Hiroaki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A telephone connection is established between a pushbutton telephone set and one of telephone lines through a pushbutton telephone set unit, a speech highway and a telephone, line unit. When one of line and extension keys of the pushbutton telephone set is pressed by the user during the telephone connection, a CPU in a control unit determines whether the telephone connection is being made based on the period of time that has elapsed after the pushbutton telephone set has captured the telephone line. If the telephone connection is being made as determined by the CPU then the, CPU controls a time switch circuit according to hold function data stored in a RAM to connect the telephone line unit …
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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 January 24, 1994 and granted December 16, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 24, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 24, 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.
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.