Copy protection system for data carriers
CA 2478372 A1 · Owner: First 4 Internet Ltd. · Inventors: Miles, Anthony
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A data payload PD is recorded on a compact disc in a format including a leadin indicating a track start address ATOC and a subchannel P which changes state at a payload start address AP, subsequent to the track start address ATOC. Data ED recorded at the track start address ATOC includes unrecoverable data. Where the data payload PD is an audio track an audio-only player begins , to search sequentially from the track start address ATOC until the subchannel changes state, and reproduces the audio track from that point. A data player on the other hand, begins to reproduce data from the track start address ATOC. When the unrecoverable data is read, the read operation is aborted as it , …
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 March 10, 2003. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended March 10, 2023.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 10, 2025.
- 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.