| 摘要 |
Transmitter coil 34, receiver 20, and security control unit 10 are mounted on vehicle 11. Doors 18 have locks 16. Unit 10 operates a fuel injection or ignition system 15 to immobilize and re-mobilize engine 14 on receipt of a command signal by receiver 20. Two (or more) portable transmitter units 22 each comprise battery 26, transmitter 24, receiver 32, and a counter with a discrete identifying number for each unit. Button 28 allows remote transmission of a door unlocking and engine re-mobilizing signal. When remobilization is required with the driver in the vehicle and the key in the steering lock 38, transmitter coil 34 transmits a series of pulses, and portable transmitters 22 count said pulses, transmitting only when the number of pulses corresponds to their identifying numbers. This ensures that only one portable unit transmits at once, avoiding possible rejection of simultaneous signals. During vehicle production, unit 10 is programmed to issue security codes to the portable transmitters; it may issue a warning or cease operation if two units have the same identifying number. Radio frequency signals are used. |
