Loop-back test system using a suppressed ringing connection
CA 2176405 C · Owner: At&T Corp. · Inventors: Garland, Stuart Mandel; Smith, David B.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The test system of the invention uses suppressed ringing connections from a test unit to the customer premise equipment via the central office to establish connections for performing the loop-back test. The suppressed ringing connections are established over standard voice trunks between a switch in the central office and the test unit by a central office service unit (COSU) such that the number of lines that can be tested simultaneously is limited only by the number of trunks linking the COSU to a switch. Because these trunks are relatively inexpensive and simple to install and maintain, the test system of the invention can be readily installed and expanded in the existing network to …
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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 13, 1996 and granted January 4, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 13, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 13, 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.