Circuit for sensing telephone line conditions
CA 2136562 C · Owner: Nortel Networks Corporation · Inventors: Kurdziel, Ryszard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A circuit for sensing telephone line conditions comprising: high impedance termination means across the telephone line; means for accumulating charge through said high impedance termination means; and electrical isolator means intermediate said means for accumulating charge and voltage detecting means.
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 November 24, 1994 and granted February 5, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 24, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 24, 2016.
- 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.