Method for keyless unlocking of an access door to a closed space
US6882268B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 20, 2002 |
| Grant date | Apr 19, 2005 |
| Priority date | — |
| Expiry date | Jun 20, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C2009/00365
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The invention relates to a method for keyless unlocking of an access door to a closed space, in particular a motor vehicle, which is carried out by an electronic system, comprising a control module for an electronic lock, associated with the door and a portable transponder for authorised users. The method comprises sending an interrogation signal at low frequency from the control module to the transponders and also the exchange of data at high frequency. The control module has reception device for the above which are at least continuously in a listening mode. The method is characterised in that the low frequency transmitters are inactive in a preliminary functional mode, the high frequency transmission device in the transponder periodically emits an activation signal for said the transmission device in order that the above are only activated during limited periods, which ensures the reception of an interrogation signal for a transponder entering the low frequency communication region.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.