Data compression
CA 2005048 C · Owner: British Telecommunications Public Limited Company · Inventors: Clark, Alan Douglas
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A data compression system in which a dictionary stores strings of characters and an encoder matches the longest of the stored strings with a current string of a data stream input to the encoder. The index of the longest matched stored string is output by the encoder and the dictionary is updated by a new string consisting of the previous match concatenated with the first two characters only of the present match. If a present match has only one or two characters it is, added without reduction.
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 December 11, 1989 and granted January 12, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 11, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 11, 2011.
- 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.