Key telephone system and interface unit for key telephone
CA 2330804 C · Owner: Niiya, Norimasa · Inventors: Niiya, Norimasa
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An interface unit connected between a telephone and a telephone network sets a data transmission speed to an optimum speed. The interface unit transmits a type query signal to the telephone terminal at a first speed. The telephone terminal transmits a type signal to the interface unit at the first speed in response to the type query signal. When the interface unit receives the type signal from the telephone terminal the interface unit changes a transmission speed to a second speed higher than the first speed if the received type signal indicates that the telephone terminal is capable of transmitting data at the second speed. The interface unit also transmits a speed change request to the …
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
- Filed January 12, 2001 and granted April 8, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 12, 2021.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 12, 2023.
- 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.