Antitheft method for a vehicle electronic apparatus

摘要

The different accessories for a vehicle e.g. CD player, radio, navigation unit etc, are each programmed with a security code. This is linked to the vehicle system by a data bus. When the accessory is switched on the data bus interrogates the various security codes and either allows operation of the accessory or de-activates it. The system operates after a set time delay from starting the vehicle. No manual programming of security codes is required even after the vehicle battery is replaced. The initial installation into the vehicle programmes the codes into the data bus.