I have spent some effort in researching how various electronic tagging systems work. There are various methods that they use including RF resonant tank absorption, RF mixing, acousto magnetic resonance, and magnetic principles. Here is what I have discovered.
This is access number to this page.
Electronic Article Surveillance (or EAS for short) involves attaching a special tag or target to items for sale in retail establishments. The tag has special electronic or magnetic characteristics which can be detected by special electronics at the exit of the store. Reusable tags are used on clothing items such as coats and pants, and cannot be removed without damaging the article unless a special detacher is used on the tag. A variation on this is the soft plastic tag, which is used on items such as ties and scarves. This is a less obtrusive tag, so it doesn't interfere with the potential purchase as much. Disposables are adhesive tags which are electronically deactivated before the article is removed from the store. These tags are usually attached to packaging items and are disposed of with the packaging. Hard tags can also be used with items such as power tools if they are attached using a special lanyard, which is a tough wire that can be pinned closed with a tag.
If a tagged item is removed from the store, the alarm will probably go off, alerting the sales associates that someone may be attempting to take something from the store. The two main problems are that the alarm may go off when it shouldn't, and fails to go off when it should. These shortcomings are addressed somewhat in the following sections. In any event, you should make sure that you have some sort of procedure in place for when the alarm goes off.
Ted Park, tpark@beer.org
