Secret communication apparatus
CA 2073784 C · Owner: Hane, Toshihisa · Inventors: Hane, Toshihisa
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This secret communication apparatus used in an audio and data transmission system has scramble/descramble circuits formed of programmable logic means. A control circuit in the apparatus instructs the programmable logic means to alter the arrangement of scramble/descramble circuits in accordance with the control signal received from the partner of communication. The control circuit in the partner's apparatus also instructs its programmable logic means to alter the arrangement of scramble/descramble circuits.
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 July 14, 1992 and granted September 23, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 14, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 14, 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.