Apparatus for interfacing analog telephones and digital data terminals to an isdn line
CA 2084108 C · Owner: American Telephone And Telegraph Company · Inventors: Fornek, Martin James; Meade, Steven Patrick; Kinn, Dennis Ralph
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An interface to an integrated service, digital network (ISDN) line for up to two analog dual tone, multifrequency telephones and up to four personal computers or data terminals. A stored program-controlled processor controls access to the ISDN line for the analog and digital interface circuits. The processor also provides access to switch-controlled ISDN features for the analog telephones (e.g. call waiting call hold, etc.).
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 30, 1992 and granted January 7, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 30, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 30, 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.