Passive response communication system
US6992568B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 2002 |
| Grant date | Jan 31, 2006 |
| Priority date | — |
| Expiry date | Nov 21, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C2209/61
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A method of passive response communication, especially for an access control system, in which a first transponder (2) transmits an interrogation signal to a remote second transponder (3), which responds by transmitting data back to the first transponder (2), the two transponders each comprising a transmitter and a receiver, and a communication signal exchanged between said transponders (2, 3) in at least one direction including a plurality of anti-relay-attack pulses (13, 14). At least one distinguishing pulse (14) selected among the anti-relay-attack pulses has a distinctive shape and the receiver of said communication signal is selectively responsive to the shapes of said plurality of pulses (13, 14). Interception of the transmitted signal in a relay attack using digital transceivers will not relay the distinctive shape and the response of the second transponder is inhibited.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.