Digital key telephone system
CA 1304482 C · Owner: Bnr Inc. · Inventors: Smelters, Paul Joseph; Chapman, Alan Stanley John; Robertson, David Joseph
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Communication paths in a digital key telephone system are operated by sequentially transferring bit states from origin channels associated with communication ports to exclusively dedicated time slots in a parallel transmission medium. Time slot bit states are selective stored at designated memory locations corresponding to destination channels associated with the communication ports. The memory locations are read in synchronizm with the channel occurrences and bit states from the designated memory locations are asserted in the corresponding channels, any remaining channels having predetermined bit states asserted therein.
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 June 30, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 30, 2009.
- 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.