Activatable/deactivatable security tag for use with an electronic security system.

摘要

A security tag is disclosed for use with an electronic security system for a controlled area. The tag comprises circuitry for initially establishing a resonant circuit (14) having a first resonating frequency within a first frequency range which is outside of the range of the detection frequency of the electronic security system. The tag is activated by changing the resonating frequency of the resonant circuit (14) to a second frequency within the detection frequency range by exposing the resonant circuit to electromagnetic energy within the first frequency range at the predetermined minimum power level to short-circuit a first circuit component (C4). The tag is deactivated by again changing the resonant frequency of the resonant circuit (14) to a third resonant frequency within a third frequency range which is also outside of the detection frequency range by exposing the resonant circuit (14) into electromagnetic energy within the detection frequency range of at least a predetermined minimum power level to short-circuit a second circuit component (C2). <IMAGE>