Solid state telephone line circuit
CA 2031180 A1 · Owner: Gartner, Todd H. · Inventors: Patel, Lalit O.; Gartner, Todd H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A solid state telephone line circuit is disclosed which is connected via a subscriber loop to a subscriber station and via a PCM bus to a central office switching system. The solid state telephone line circuit of the present invention includes an interface circuit having a, voltage to current converter connected to the subscriber loop. The voltage to current converter converts feed voltage from a central office battery to loop feed current on the subscriber loop. A differential amplifier circuit connected to a sensing network develops an, output voltage that is proportional to the voltage dropped across the subscriber loop and sensed by the sensing network. A control circuit having a loop …
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 29, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 29, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 29, 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.