Hands-free telephone
CA 2021793 C · Owner: Murata, Yukio · Inventors: Murata, Yukio
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A hands-free telephone for use on a vehicle and having a handset incorporating a radio section therein and a hands-free adapter incorporating a hands-free telephone unit therein. To eliminate howling this kind, of telephone generally needs two variable attenuators or variolossers, each for changing the level of respective one of a receive and a transmit signal to be applied to a speaker of a hands-free telephone unit and a radio section, respectively, so as to maintain the two levels in a predetermined relation, and a variable resistor for adjusting the volume of voice to be outputted by the speaker. In the present invention, the variable resistor is implemented by a variable resistor which …
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 July 23, 1990 and granted October 4, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 23, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 23, 2012.
- 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.