Arrangement for simultaneously interrogating a plurality of portable radio frequency communication devices
CA 2128596 C · Owner: American Telephone And Telegraph Company · Inventors: Mandelbaum, Richard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An updatable, interrogation system is provided for simultaneously interrogating a plurality of portable data cards. Operable over a plurality of radio frequencies, the interrogation system sequentially communicates with each portable data card as it comes within communication range on a first one of the plurality of radio frequencies for determining a unique identification number associated witheach data card. Once the identification number for a card is obtained by the interrogation system, a predetermine transaction such as deactivating an electronic, barrier to entering a limited access area for the holder of the identified card is initiated. The interrogation system then selects and …
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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 21, 1994 and granted March 30, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 21, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 21, 2016.
- 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.