Method of selecting an electronic module from a plurality of modules present in the interrogation field of a terminal
US6337619B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 1998 |
| Grant date | Jan 8, 2002 |
| Priority date | — |
| Expiry date | Nov 6, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/0008
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for selecting an electronic module from a plurality of at least two modules (M1, M2, M3) capable of emitting messages simultaneously, includes the steps of sending a general query message (ACTIVALL) to the modules, and selecting (AFI, SELECT-ID) the module having responded first, the modules, on receiving a query message (ACTIVALL, ACTIV), determining a random time interval (P) and sending a responding message (ID, R) when the said time interval (P) has elapsed. A module is set in idle position (IDL) when it receives a message (MESS) before the time interval (P) preceding the sending of a response (ID, R) has elapsed. The idle position (IDL) is at least characterized by the fact that one module does not respond, subsequently, to a complementary query message (ACTIV). This invention is particularly useful for contactless smart card readers and for terminals for electronic labels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.