Antitheft system for a car stereo having a detachable grille

摘要

An antitheft system, for car stereo having a detachable grille, has an identification resistor provided in the body of the car stereo, and a resistor provided in the grille. A circuit including the identification resistor and the resistor in the grille is formed when the grille is attached to the body of the car stereo. A voltage across the identification resistor is compared with a reference voltage for producing a coincident signal when the voltage is equal to the reference. In response to the coincident signal, the car stereo becomes operative.