Deactivation and coding system for a contactless antitheft or

Abstract

A deactivation and coding system for a contactless antitheft or identification label, uses a pyrotechnic material to burn away a track portion, whereby an electrical connection is severed. The labels in the system according to the invention consist of tuned circuits in the form of one or more coil/capacitor combinations. Deactivation can be effected by severing the connection between a coil and the associated capacitor. Coding can be effected by severing the connection with one of several parallel-connected coils or capacitors. Coding can also be effected by removing an initial short-circuit of one of several series-connected capacitors. The pyrotechnic material may consist of one or a combination of the mixtures Pb.sub.3 O.sub.4, Si, Ti and Fe.sub.2 O.sub.3 ; PbCrO.sub.4, and Zr; Pb.sub.3 O.sub.4, Si and KNO.sub.2 ; and Pb.sub.3 O.sub.4 and Si or a mixture having comparable properties. The heat released during the combustion reaction can be used in combination with a thermosensitive paper for the purpose of causing readable information to appear on the label upon deactivation or coding. The use of protective foils can prevent damage to the goods on which the labels are provided.