Method for operating an access control system, in particular for a motor vehicle, and access control system
US6834179B2 · kind B2 · utility
2Cited by
5References
15Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jan 30, 2002 |
| Grant date | Dec 21, 2004 |
| Priority date | — |
| Expiry date | Jan 20, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C2009/00793
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
In the access control system, a code transmitter-end transceiver unit and a vehicle-end transceiver unit emit signals approximately synchronously on approximately the same carrier frequency. As a result of superimposition, a new code signal arises and its code information item is compared with an expected set point code information item. When there is correspondence, an enable signal for locking or unlocking or releasing the immobilizer is generated. The synchronous transmission/reception makes illegitimate monitoring more difficult.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.