Key telephone system
CA 2103302 C · Owner: Kabushiki Kaisha Toshiba · Inventors: Komuro, Isaku
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A telephone system provided with a key service unit having ports to which terminal telephone sets are connected. The unit has a first memory having memory areas each for storing at least one customer data for each port; a second memory for storing the data temporarily; and a control section for transferring the data between the memory areas through the second memory. The data to be transferred is first transferred from the first memory to the second memory temporarily; secondly data stored in a transfer destination memory area of the first memory (for a port to which a terminal set is newly connected) is transferred to a transfer start memory area of the first memory at which the data to be …
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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 November 17, 1993 and granted May 13, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 17, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 17, 2015.
- 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.