NCJ Number
61027
Date Published
1978
Length
5 pages
Annotation
AN ELECTRONIC SURVEILLANCE SYSTEM DEVELOPED IN THE UNITED STATES AND PRODUCED BY A EUROPEAN MANUFACTURER TO MINIMIZE THE INCIDENCE OF SHOPLIFTING IS DETAILED.
Abstract
THE KEY TO THE OPERATION OF THE ELECTRONIC SURVEILLANCE SYSTEM IS A TAG. THE TAG IS ABOUT 3 INCHES IN LENGTH AND IS VERY THIN. IT CAN BE READILY DISGUISED AS MANUFACTURER INFORMATION LABELS OR HIDDEN IN SUCH PLACES AS THE COLLAR OF A SHIRT OR THE HEM OF A GARMENT. THE TAG CONSISTS OF TWO METALS, MOLYPERMALLOY AND VICALLOY. THE TAG INTERROGATION PROCESS IS ACCOMPLISHED BY A RAPIDLY SWITCHING MAGNETIC FIELD. MOLYPERMALLOY MATERIAL RESPONDS WHEN INTERROGATED BY THE MAGNETIC FIELD, AND VICALLOY MATERIAL GIVES THE TAG ITS UNIQUE DEACTIVATION-REACTIVATION PROPERTIES. PROPER TAG INTERROGATION REQUIRES THE GENERATION OF HIGH-FREQUENCY MAGNETIC FIELDS THAT HAVE PARTICULAR MAGNITUDE AND DIRECTION. THE RESPONSE FROM AN ACTIVE LABEL IS DETECTED BY A MULTITURN DETECTOR ANTENNA. ALARM CIRCUITRY OUTPUTS CAN BE USED TO DRIVE A WIDE VARIETY OF INDICATORS OR ALARMS. TYPICAL ARE OUTPUTS USED TO BAR THE DOOR, ACTIVATE A LIGHT, SOUND A BUZZER, OR REMOTELY ALERT THE SECURITY OFFICE. ILLUSTRATIONS AND PHOTOGRAPHS OF THE ELECTRONIC SURVEILLANCE SYSTEM ARE INCLUDED. (DEP)