Method and apparatus for providing a private communication system in a public switched telephone network
CA 2481368 C · Owner: Rogers, Steven L. · Inventors: Yafuso, Byron Y.; Lekven, Eric J.; Rogers, Steven L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A private communication network through which a plurality of member users communicate using the public switched telephone network (PSTN) (10) is disclosed herein. Each member user utilizes either a modified land line telephone (48) directly connected to PSTN (10) or uses a modified mobile telephone (22) operatively coupled to the PSTN through a wireless communication system (14). The private communication network includes network call manager (40) having a telephone network interface (92) for establishing a telephone connection with each of a plurality of telephone lines (44) of the PSTN (20). Each of the plurality of telephone lines (44) is associated with one of the plurality of member …
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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 29, 1997 and granted December 4, 2012. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 29, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 29, 2019.
- 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
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.