Automotive electronic communication apparatus with theft disabling, particularly car radio or similar automotive audio equipment
US4808981A · kind A · utility
14Cited by
5References
12Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 29, 1988 |
| Grant date | Feb 28, 1989 |
| Priority date | — |
| Expiry date | Mar 29, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/22
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
To prevent overriding an electronic car radio theft disabling system by connecting an external battery to a car radio prior to theft thereof, the radio includes a measuring circuit (7, 7') measures the impedance of a connected accessory, for example a loudspeaker or loudspeaker system (8), and if the impedance of connected loudspeaker does not match the impedance stored in a memory (5) of the car radio, operation of the radio is inhibited until the appropriate code word--known only to the proper owner--is reinserted.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.