Telephone circuit assembly with hook-off detector circuit
CA 2068971 C · Owner: Siligoni, Marco · Inventors: Siligoni, Marco; Saviotti, Vanni
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A circuit assembly is disclosed which, comprises: an interface circuit (3') between the, subscriber line (L) and exchange devices of the kind with two amplifiers connected in a bridge configuration (9A,9B) between the battery (UB) terminals and having a means (15) of detecting the output currents (IA,IB); a supply circuit (5') which includes the exchange battery (UB) and a ring generator (AC'); a switch-over means (7) for putting the line (L) through the interface circuit (3') or the supply circuit (5'); two bridge resistors (RP,RP') which are in series with the line (L) when the latter is connected to the supply circuit (5') and of which one (RP') is connected permanently between one (A) …
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 May 19, 1992 and granted January 22, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 19, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 19, 2014.
- 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.