Subscriber line interface and power circuit
CA 2172563 C · Owner: Gammel, John C. · Inventors: Marsh, Andrew J.; Spires, Dewayne Alan; Roy, Apurba
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A subscriber line circuit which truly implements all of the BORSCHT functions and which does not rely on an external ringing generator to provide the ringing voltage when needed is disclosed. This implementation is achieved by recognizing that supervisory and ringing signals occur in some sort of sequence and therefore, do not, have to be generated simultaneously. Based on this recognition we provide a circuit, which truly implements all of the BORSCHT functions and includes a power sectionthat generates each of the supervisory signals e.g. -48 volts and -24 volts, and, alerting signal e.g. ringing signal, in turn and as required.
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 March 25, 1996 and granted February 1, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 25, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 25, 2018.
- 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.