Telephone system allowing hold releasing request from central office line
CA 1292816 C · Owner: Wakabayashi, Tamotsu · Inventors: Tsurusaki, Masayuki; Mori, Hideyasu; Wakabayashi, Tamotsu
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A telephone system which allows external releasing of a holding state set by a holding operation of a telephone set. A signal receiving circuit of the system receives such a holding-state releasing signal as a DTMF signal or the like sent from a central office line to release the hold state of the telephone set on the basis of an output of the circuit.
Read 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 December 3, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 3, 2008.
- 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.