The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 19, 2005
Filed:
Jun. 20, 2002
Thierry Roz, Les Hauts-Geneveys, CH;
Marc Degrauwe, Chez-le-Bart, CH;
Thierry Roz, Les Hauts-Geneveys, CH;
Marc Degrauwe, Chez-le-Bart, CH;
EM Microelectronic-Marin SA, Marin, CH;
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.