Understanding the Technologies – AM and RF

Electronic Article Surveillance (EAS) systems protect merchandise by creating a detection zone at store exits. When an active security label or tag passes through this zone without being removed or deactivated at checkout, the system triggers an alarm.

The two most widely used EAS technologies are RF (Radio Frequency) and AM (Acousto-Magnetic). Although both serve the same purpose, they differ significantly in detection range, gate design, and performance in real retail environments.

RF (Radio Frequency)

  • Frequency: 8.2 MHz (radio waves)
  • Typical detection range: up to 1.85 m
  • Lower installation cost and wide retailer acceptance
  • Commonly used with flat, sticky soft labels
  • Easy and fast deactivation at checkout
Limitations
  • Poor perfomance and detection with metal items: Metal reflects radio frequencies (RF), disrupting the tag’s antenna and preventing it from getting enough power to transmit.
  • Generally more false alarms
  • Higher risk of false alarms
  • Detection usually limited to visible doorway pedestals

AM (Acousto-Magnetic)

  • Frequency: 58 kHz (sound / acoustic waves)
  • Typical detection range: up to 2.7 m
  • Much wider detection zone than RF
  • Highly resistant to electronic interference
  • Generally less false alarms
  • Reliable detection near metal and foil packaging
  • Supports concealed and in-floor antenna installations
Limitations
  • Labels are thicker with a raised profile
  • Labels cannot be bent or printed on
  • Labels for AM, called DR labels are generally a higher price than RF labels.
How the technology works
Consumer electronics
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AM technology usage

EAS systems create a detection field at store exits using antenna gates. When an active security label or tag enters this field without being removed or deactivated at checkout, the system detects a response signal and triggers an alarm.

RF systems transmit 8.2 MHz radio waves. RF labels resonate inside this radio field and reflect a signal back to the antennas.

AM systems transmit 58 kHz magnetic pulses that generate acoustic (sound) waves inside the tag. These sound waves are detected by the antennas, enabling wider gate spacing and reliable performance near metal.

Retail Security Technology Guide

Understanding RF, AM & RFID

For somebody seeing these technologies for the first time, the easiest way to understand them is this: RF and AM are mainly used to help stop theft, while RFID is used to identify and track products individually. All three use invisible signals, but they work in different ways and serve different purposes in retail.

In simple terms, retail security systems are trying to answer one of two questions: Has an unpaid product passed through the exit? or What exact item is this, and where is it in the business? RF and AM focus on detection at the exit, while RFID focuses on item-level visibility and stock accuracy.

RF Continuous signal used for exit detection
AM Pulse-and-listen system for precise detection
RFID Unique item identification and inventory visibility
RF / Radio Frequency

RF

A continuous signal used to detect a tagged item at the exit

RF stands for Radio Frequency. In retail, it is commonly used as an electronic article surveillance system to help detect products leaving the store without being deactivated or removed at checkout.

How it works

The gates create a continuous signal between them. A compatible RF tag or label on the product reacts when it enters that field. The system recognises that response and triggers an alarm if the tag is still active.

Simple way to picture it

RF is a little like a radio station broadcasting all the time. The gates are always sending out a signal, and the tag responds when it passes through.

In plain English: RF is an always-on signal looking for a reaction from a tag.
AM / Acousto-Magnetic

AM

A pulse-and-listen system designed for very clear detection

AM stands for Acousto-Magnetic. Like RF, it is used for exit protection, but it works in a different way. Instead of sending a continuous signal, the system sends a short pulse and then listens for the tag to respond.

How it works

The gates send out a brief magnetic pulse. The AM tag reacts by vibrating and sending back a recognisable signal. The system listens in the quiet moment after the pulse, which gives it a very clear detection method.

Simple way to picture it

AM is like tapping a bell and listening to it ring. The system creates the tap, then waits to hear the tag respond.

In plain English: AM sends a quick signal, goes quiet, and listens for a very clear reply from the tag.
RFID / Radio Frequency Identification

RFID

Item-level identification used for inventory visibility and product tracking

RFID stands for Radio Frequency Identification. Unlike RF and AM, RFID is not only about detecting whether a product is present. It is designed to identify each item individually using a unique ID stored on the tag.

How it works

An RFID reader sends out a signal to nearby tags. Each tag responds with its own unique identity, and the software matches that ID to product information such as model, size, colour or stock record.

Simple way to picture it

RFID is like a barcode that does not need to be seen. It can identify one item or many items at the same time, without scanning them one by one.

In plain English: RFID does not just tell you that something is there — it tells you exactly what it is.

The simplest way to understand the difference

RF

A continuous signal used to detect an active tag passing through the exit.

AM

A pulse-and-listen system where the tag gives a clear response after the signal is sent.

RFID

A product identification technology that gives each item its own identity within the system.

EAS Sectors
DIY & Home Improvement
AM
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AM Technology
RF
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RF Technology

Why it trends this way

DIY stores contain many metal items and dense fixtures that interfere with RF. AM performs reliably and supports wider gate spacing.

Fashion & Apparel
AM
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AM Technology
RF
0%
RF Technology

Why it trends this way

AM allows wider entrances and concealed installations, creating a cleaner storefront experience for fashion retailers.

Health, Beauty & Pharmacies
AM
0%
AM Technology
RF
0%
RF Technology

Why it trends this way

AM provides superior detection in busy environments and maintains performance against foil-lined concealment attempts.

Supermarkets & Hypermarkets
AM
0%
AM Technology
RF
0%
RF Technology

Why it trends this way

RF dominates due to low-cost labels and high volumes, while AM is used in higher-risk zones or wider entrances.

Consumer Electronics
AM
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AM Technology
RF
0%
RF Technology

Why it trends this way

AM systems work well around metal-rich products and support concealed installations at wide entrances.

Sporting Goods
AM
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AM Technology
RF
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RF Technology

Why it trends this way

AM suits wide entrances and bulky merchandise, providing consistent detection across large store layouts.