Activatable/deactivatable security tag for use with an electronic security system
US5103210A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 1990 |
| Grant date | Apr 7, 1992 |
| Priority date | — |
| Expiry date | Jun 27, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2431
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
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 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 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. The tag is deactivated by again changing the resonant frequency of the resonant circuit to a third resonant frequency within a third frequency range which is also outside of the detection frequency range by exposing the resonant circuit to electromagnetic energy within the detection frequency range of at least a predetermined minimum power level to short-circuit a second circuit component.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.