Circuit and method for reducing common mode interference in telephone instruments
CA 2193154 C · Owner: Lucent Technologies, Inc. · Inventors: Wittman, Brian Albert
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A circuit for, and method of, reducing cross-coupled interference between first and second telephone lines of a multi-line telephone instrument and a telephone instrument containing the same. The circuit includes: (1) a first differential input amplifier having first tip and ring inputs coupled to conductors of the first telephone line and first tip and ring shunt resistors coupling the first tip and ring inputs to a signal reference of the telephone instrument and (2) a second differential input amplifier having second tip and ring inputs coupled to conductors of the second telephone line and second tip and ring shunt resistors coupling the second tip and ring inputs to the signal …
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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 December 17, 1996 and granted March 7, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 17, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 17, 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.