Understanding Tag and Alarm Systems

With shoplifting on the rise like never before (over $25 billion in the United States alone), the implementation of an effective anti-shoplifting system can be the best business decision a retailer will ever make. There are several systems to consider when dealing with what is referred to in the industry as shrinkage or loss prevention.

One of the easiest and earliest methods of preventing theft is to simply lock everything down. While this prevents your merchandise from leaving the store, it makes your merchandise inaccessible to your customers and makes the merchandise hard to move around and so on. If this is not a problem, then you might consider wire lanyards which are a popular method of securing clothing articles to a rack. They are extremely strong and not that hard to remove, although you will still need to pay someone to remove it just so your customer can look at the item.

Another popular tool for reducing shrinkage is the combination of security guards and a closed circuit television surveillance system. This system not only prevents theft, it educates the retailer on how to recognize repeat offenders by allowing them to study shoplifting patterns and behavior. Video and recording devices can be hidden anywhere, are small and hard to see. The problem is that these systems can be expensive and they are only as good as the people using them, i.e., the sleeping or distracted security guard.

To overcome these shortcomings, anti-shoplifting professionals have come up with a way to secure merchandise without compromising their accessibility. Most experts agree nowadays that a tag and alarm system is the most effective anti-shoplifting device on the market today. Known as the electronic article surveillance (EAS) system, this system allows you to identify merchandise as it is transported through a gateway (usually two pedestals). Not only does this system prevent shoplifting, the latest developments promise to increase the bottom line by increasing sales, lowering labor costs, and improving inventory control.

Existing EAS Systems

There are currently three Tag and Alarm Systems on the market today:

The RF System - Radio Frequency
The EM System - Electromagnetic
The AM System - Acousto-Magnetic

In each system, a tag or label is attached to a piece of merchandise. When the tag or label is transported through a gateway, an alarm will sound unless the tag has been deactivated by a sales clerk using a detacher or a hand held scanner. Until the system is developed that can read a variety of tag technologies, each system has its limitations when it comes to the surveillance area that it can cover which is determined by the frequency range and the strength of that frequency.

The RF System

The most popular system is the Radio Frequency System. In this system a label -- a disposable electronic circuit and helical antenna - responds to a specific frequency emitted by a transmitter which is picked up by an adjacent receiver. At the end of the antenna is a small diode or RC network that causes the tag to emit a radio signal in response to the radio signal it receives. When the receiver responds with a much stronger RF pulse, this burns out the diode or RC components in the antenna. Since the burned out tag does not emit a signal, the gates allow it to pass without an alarm. The distance between the transmitter and the receiver cannot be more than 80 inches wide and the operating frequency range from 2 to 10 MHz.

One of the biggest problems with the RF system (and probably any EAS system that places a tag on the outside of a package) is that the thief can avoid detection simply by throwing away the package and pocketing the item. Source tagging solves this problem by embedding the disposable RF security label at either the point of manufacture or packaging. Hence its success in the packaged products industry. Retailers are even starting to use it for merchandise such as earrings, apparel, shoes, batteries, videocassettes, audio tapes, computer software, sporting goods and electronics.

When the packaging is so thick, made of foil or liquids, there can be a problem with detecting the signal emitted by the tag. This is solved by using the Ultra-Strip tag or label which can be detected through foil, liquids or layers of packaging.

The EM System

The electromagnetic system is used by retail chain stores, supermarkets and libraries around the world. In this system, a magnetic, iron-containing strip with an adhesive layer is attached to the merchandise. This strip is not removed by a sales clerk -- it's simply deactivated by a scanner that uses a specific highly intense magnetic field.

The electromagnetic system works by applying a low frequency magnetic field generated by the transmitter antenna. When the strip passes through the gate, it will transmit a unique frequency pattern which is picked up by an adjacent receiver antenna. The small signal is processed and will trigger the alarm when the specific pattern is recognized. Because of the weak response of the strip and its low frequency (70 Hz to 1 kHz), EM antennas are larger than those used by most other EAS systems, and the maximum distance between entry pedestals is 40 inches. .

The AM System

The newer acousto-magnetic system, which has the ability to protect wide exits and allows for quick label application, uses a transmitter to create a surveillance area where tags and labels are detected. This system uses a material that is highly magnetostrictive, which means that when you put the tag material in a magnetic field, it physically shrinks. The higher the magnetic field strength the smaller the metal becomes. The metal actually shrinks about one-thousandth of an inch over its full 1.50 inch length.

When you walk through the gate with a tag, the transmitter in the gate sends a radio frequency signal (58 kHz) in pulses, which energizes the tag in the surveillance zone. When the pulse ends, the tag responds, emitting a single frequency signal that resonates at frequency "F". The tag will continue to resonate at "F" for a short period of time, and the receiver listens for that frequency. If it hears it, it knows there is a tag and sounds the alarm. Otherwise, the transmitter stops and you walk out of the store. .