Intercom system for a key telephone system
CA 1069630 A · Owner: International Standard Electric Corporation · Inventors: Stine, Robert D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract of the Disclosure, A call selector circuit is coupled to all of a plurality of intercom stations and is responsive to a call initiating signal from one of the plurality of stations to provide a first portion of a connection to another of the plurality of stations. A call routing circuit is coupled to the selector circuit to establish a second portion of the connection. A diode matrix is coupled to the routing circuit to establish a third portion of the connection. A relay matrix is coupled to the diode matrix and all of the plurality of stations to complete the connection and enable a calling party in the vicinity of the one of the plurality of stations to page a called party in …
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
- Granted January 8, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 8, 1997.
- 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.