Wide area cordless telephone system capable of receiving incoming group address calls
CA 2035962 C · Owner: Tanaka, Kazushige · Inventors: Hashimoto, Tadao; Tanaka, Kazushige
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a wide area cordless telephone system an individual-call signal is, generated if an incoming call from the telephone network is an individual call to one of cordless stations of a group and a group-call signal is generated if it is directed to all cordless stations of the group. A group of access units are associated with the cordless station of each group to establish a control channel and speech channels with the cordless stations. The access units respond to the individual-call signal by transmitting a speech-channel identifier to one of the cordless stations through the control channel and transmitting a ringing signal through a speech channel specified by the speech-channel …
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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 February 7, 1991 and granted November 8, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 7, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 7, 2013.
- 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.