Patent ID: 6025780
Filing Date: 2000-02-15
Classification: G06K,G06Q,G07G,G08B

Abstract:
An electronic security system comprising:(a) a predefined set of passive radio frequency identification tags, each tag being associated with, and attached to, an article or packaging for an article, each tag including:(i) an antenna for detecting the presence of the article by receiving an interrogation signal and returning a response signal, and(ii) an integrated circuit connected to the antenna for storing tag information and for outputting the tag information with the response signal upon interrogation of the tag, the tag being programmed with unique tag information so that no two tags within the predefined set of passive tags have exactly the same tag information;(b) an interrogator for monitoring a detection zone for detecting disturbances in the form of a response signal caused by the presence of a tag within the zone, the interrogator outputting an interrogator output signal when a tag is detected in the zone, each interrogator output signal including the tag information stored in the integrated circuit;(c) a computerized database containing a record for each of the tags in the set, each record including the tag information;(d) a computer including a comparator for receiving the database records and the tag information from the interrogator and comparing the tag information to the database records, and outputting an appropriate response,wherein a portion of the tag information in the database is variable information which is changed in the database without any physical or electronic altering of the tag or the tag information stored in the integrated circuit, the change in the database thereby causing a virtual deactivation of the tag.