How EAS works
Electronic Article Surveillance (EAS) is a technology used to detect articles as they pass through a detection system in a store. This detection is used to alert retail staff that unauthorised removal of items is being attempted. Over a million EAS systems have been installed worldwide, primarily in retail stores, and proof their effectiveness every day.
Various EAS systems exist but two types of EAS technologies dominate the retail business. Acousto magnetic systems (AM) which operate on 58 kHz and Radio Frequency systems operating on 8.2 MHz. In each case, an EAS tag or label is attached to an item. The tag is then removed or deactivated so it will not trigger the detection system. If the tag is a reusable tag or so called hardtag, a detacher is used to remove it when a customer purchases the item it is attached to. If a tag is a disposable tag, also called stickertag, paper label or DR label, it can be deactivated by swiping it over a deactivator pad. If the label has not been deactivated or detached by retail staff, an alarm will sound when it passes the gates.
The use of EAS systems does not completely eliminate shoplifting but can reduce theft with up to 70% or even more when used in combination with, for example, camera systems.
Sourcetagging is the process whereby an inexpensive tag or label, either AM or RF is integrated into the product or its packaging by the manufacturer.
Radio Frequency (RF)
Radio Frequency (RF) Systems are very popular and produced by multiple manufacturers. The disposable labels are small and paper-thin. This is the reason that they are also named paper labels or stickertag.RF labels, basically a miniature electronic circuit and antenna, attached to a product respond to a specific frequency transmitted by a pedestal at the entry/exit of a store. The response from the label is then picked up by a receiver antenna. The receiver processes the label response signal and will trigger an alarm if the signal matches defined criteria. The distance between two gates or pedestals, can be up to 2 metres. Operating frequencies for RF systems range from 1.8 to 10 MHz. As -different from hardtags- RF labels operate on 8.2 MHz, this is also the most commonly used frequency.
Transmitter and Receiver can be combined in 1 antenna frame; called mono systems. Mono systems are used when the store entrance is small and also popular in Supermarkets as they limit the number of antennas required for the checkout aisle.
There are multiple manufacturers of RF systems. Checkpoint (www.us.checkpointsystems.com) is one of the largest US based manufacturers. Nedap (www.nedap-retail.nl) in the Netherlands is one of the older European manufacturers. The German manufacturer MTC (www.easpartners.com) offers both RF and AM technology.
Acousto Magnetic (AM)
Acousto Magnetic (AM) systems have the ability to protect exits up to 2.40 metres using disposable labels. The system uses a transmitter signal of 58 kHz in pulses, which energises a tag in the detection zone. When the pulse ends, the tag responds, emitting a single frequency signal. While the transmitter is switched off between pulses, the tag signal is detected by a receiver. And if the signal meets all the criteria, the alarm will sound.
AM labels or tags are composed by 2 amorphous metal plates. An AM deactivator is used to deactivate or reactivate an AM labels.
The advantage of an EAS system based on AM technology is the larger detection distance compared to RF systems and the relatively small size of the AM Label. Furthermore, because lower frequencies are being used, labels are also detected better when placed in metal shopping trolleys. The disadvantage is that AM labels are three dimensional and despite the small size cannot be used on rounded surfaces.
AM technology was developed a few decades ago by Sensormatic (www.sensormatic.com) but are also produced today by multiple other manufacturers including the German company MTC, (www.easpartners.com).