Electronic remote control means, especially for centrally controlled locking systems in motor vehicles
US4847614A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 28, 1987 |
| Grant date | Jul 11, 1989 |
| Priority date | — |
| Expiry date | Sep 28, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C2009/00769
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The electronic remote control means operates according to the known principle of code stepping through which a different code word is used after each transmitting/receiving operation. In accordance with the invention the respective new code word is produced anew by linking according to a given function, starting from a stored original code word and the previous code word. In case of non-agreement between the code word received and the new code word determined at the receiver additional code words are produced in sequence at the receiver. Thereafter, if no agreement results, the receiver switches over to an increased security mode wherein two successive code words in sequence must be successfully compared.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.