Digital key telephone system
CA 1296413 C · Owner: Tsurusaki, Masayuki · Inventors: Tsurusaki, Masayuki; Shiomi, Junichi; Sano, Yoshikazu
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a digital key telephone system through which extension-to-extension calls can be made and incoming calls can be transferred between a master main installation and plural slave main installations the, master and slave main installations are interconnected through digital interface units provided for each installation in order to transmit and receive speech data and control data in digital code between the installations. The digital interface unit of the master main installation first designates an address of the slave main installation to which data are to be transmitted before data transmission, while the digital interface unit of the slave main installation receives data transmitted …
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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
- Granted February 25, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 25, 2009.
- 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.