Coded objects identifiable by proximity and devices for changing the codes of these objects
US4857913A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1987 |
| Grant date | Aug 15, 1989 |
| Priority date | — |
| Expiry date | Nov 25, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/0724
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The invention relates to electronic badges equipping portable objects, such as plastified cards and capable of being identified at a distance by suitable readers in order to ensure operation such as the unlocking of a lock. These badges are of a passive type, that is to say supplied exclusively from the outside by inductive coupling and they are in addition of a type reprogrammable through channels, each comprising an inductive coupling (at the level of inductances) from a suitable apparatus. The circuitry for forming the binary coded identification signals of the badge comprise a dead memory, a life memory or buffer and a rapid reading and writing circuit which provides the connections between these two memories, as well as the connections between the dead memories and the reprogramming channels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.