Comparison of RF & AM TechnologiesAn anti-theft system, an electronic device designed to prevent shoplifting and shrinkage, consists of accessories applied to the products that need protecting and sensor gates located at the various entry and exits points in-store.
When an anti-theft tag enters the detection field of the antennas, a visual and/or audible alarm is triggered, alerting store personnel. At the time of purchase, the anti-theft devices are released or deactivated by the cashier. A store tag can also be self-alarming: in addition to the antenna alarm, the anti-theft accessory has its own alarming system that is automatically triggered if a thief tries to detach it or cut the cable.
Two main technologies are used today for the production of anti-theft equipment : radio-frequency and acousto-magnetic.
Present mainly in grocery, textile, multi-media and convenience stores, or used largely for source protection, radio-frequency anti-theft devices are the most common on the market due to their efficiency and affordable price. They work thanks to radio waves (global standard of 8,2 MhZ) : a weak signal circulates between the two anti-theft antennas (in general a transmitting and a receiving antenna, but there are also mono antennas which can both transmit and receive signals). If an anti-theft accessory comes into contact with this signal, the frequency shifts and triggers the alarm.
RF labels, which are customizable, can be "deactivated" during the sales process thanks to a deactivation plate, a device placed on (or under) the checkout counter.
Acousto-magnetic, the most recent technology invented by the American company Sensormatic®, is generally recommended for department stores, luxury stores, pharmacies, perfume and cosmetics stores, or even DIY and gardening stores. This anti-theft system is popular for three reasons :
- It has a higher detection rate that can cover wide passages of up to 94 inches / 2.40 metres depending on the model ;
- The labels are small, offering a discreet anti-theft solution for the protection of small items;
- Also, this technology is particularly effective on aluminized packaging.
Acousto-magnetic anti-theft tags consist of 2 to 3 ferromagnetic stips generally based on a frequency of 58 KhZ. The principle is the same as for radio-frequency : when the accessories penetrate the detection field of antennas using the same frequency, the frequency increases, triggering the alarm. AM accessories can even work on non-ferrous metals, unlike RF tags that are neutralized by aluminized packaging.
To reinforce security in your store, it can sometimes be necessary to complete your anti-theft installation with systems capable of countering different theft techniques, such as aluminum linings in bags or clothing (using metal detectors).
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