Enhanced subscriber line interface circuit
CA 2042675 C · Owner: Ag Communication Systems Corporation · Inventors: Naseer, Absar; Warner, Michael; Patel, Lalit O.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An enhanced subscriber line interface circuit for a digital switching system over which a connection is established between a digital switching system and a subscriber instrument via a subscriber line. The enhanced subscriber line interface circuit includes a line configuration and protection circuit connected to the subscriber line and to a thick-film hybrid module. The thick-film hybrid module comprises in combination a high voltage interface circuit and a PCM conversion circuit. The high voltage interface circuit provides power to the subscriber line, converts received analog voice signals transmitted from the subscriber instrument into differential voltage voice signals and detects the …
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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 15, 1991 and granted October 6, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 15, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 15, 2013.
- 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.