Isdn callback device for testing telephone line
CA 2238638 A1 · Owner: Soto, Roy L. · Inventors: Soto, Roy L.; Lester, James W.; Lowell, Alan B.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An ISDN callback device installable in a telephone network facility and configured to, pre-qualify and test ISDN telephone circuits that either relatively upstream of the ISDN callback device (toward a central office line card) or relatively downstream of the ISDN callback device (toward a network termination, such as a craftsperson's test set or customer premises equipment). The ISDN callback device contains two individually controllable, communication/test interface one of which is operative to emulate a subscriber premises ISDN terminal device, in a network termination (NT1-TE) mode of operation and the other of which, is controllably operative as either a network termination (NT1-TE) …
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 May 25, 1998. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 25, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 25, 2020.
- 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.