An antitheft device for vehicles includes a central unit able to inhibit or enable normal function of the vehicle engine responsive to a coded radio signal emitted by a portable unit activated by a radio signal emitted by the central unit. The central unit includes a first memory, a device to transmit...http://www.google.com/patents/US5280267?utm_source=gb-gplus-sharePatent US5280267 - Passive action antitheft device
