Do Barcodes Set Off Security Alarms?

Barcodes help companies to track large stocks accurately, which saves more money and time. Barcodes decrease the theft of your assets and provide peace of mind. Using anti-theft barcode alarm systems has been proven to have a demonstrable reduction in loss or liability.

Barcodes set off security alarms using anti-theft barcode alarm systems. Through this blog, I will discuss more barcodes and security alarms.



A barcode is a pattern consisting of lines and gaps of varying width. A barcode scanner can read this square or rectangular pattern, which assigns numbers to it. Barcodes can identify products quickly.

Barcodes began to encode information about the product and its retail price. The barcode’s development was triggered by the need for technical standards in the booming grocery and auto parts industries during the 1960s. Representing the Morse code Norman Joseph Woodland drew a series of lines in the sand and developed the concept of the barcode.

Barcodes come as:

  1. 1-dimensional (1D) barcodes – has text information, such as product type, size, and color
  2. 2-dimensional (2D) barcodes – complex and have more details, including the price, quantity, and sometimes an image.

Barcode Reader

A barcode reader or the barcode scanner captures and decodes information in the barcode. Then the reader links to a host computer and displays the information scanned from the captured image.

NCR company developed the first commercial scanner to read barcodes. Nowadays, barcodes are used in many places, from retail stores to warehouses. They’re often used as part of the purchase process and for inventory tracking and accounting assistance. There are many other ways they’re being used right now too.

Barcode readers are a powerful and cost-effective way to automate data collection. These devices can save valuable time and money for companies by reducing human error and expediting processes such as tracking inventory, managing assets, and monitoring point-of-sale transactions.

A barcode scanner typically consists of the illumination system, the sensor, and the decoder. The main components of a barcode are:

  1. Light source – helps you read and decode the information in a barcode to be accurately scanned.
  2. Lens – scans the barcode. 
  3. Photoconductor – converts optical impulses into electrical ones. 
  4. Decoder – Decoder decodes barcodes and sends them to your scanner 


UPC are Universal Product Codes and types of barcodes common in retail stores. These barcodes are used to track inventory, get information about the product, get pricing information, and more. The UPC is made up of 12 numbers broken into three sections: 6 digits for the manufacturer’s code, 4 digits for the retailer’s code, and 2 digits for the item.

SKU or Stock Keeping Unit is an internal product inventory code unique to each company. If you compare the SKU of the same product at two different stores, you’d see that they were different. Each store assigns its own SKU to products during the ordering process. The SKU helps identify, organize and track items in inventory.

UPC symbol is the barcode label or barcoding on the backside of a product, and the SKU is typically found on a store’s unique shelf pricing. 

Do Barcodes set off Security Alarms?

What triggers the alarm is a magnet placed near the barcode. When you pay and buy a product, the cashier disables it by scanning and demagnetizing the item. The system can detect if you have not unlocked the magnetic barcode through anti-theft adhesive barcode labels. If the item is not demagnetized, once it goes through the sensors on the main door, it will trigger the detonation of the security alarm. 

The security system at the store is not effective at preventing theft.

To prevent people from taking products out of the store without paying, barcodes anti-theft adhesive labels are installed on items. This allows an alarm system to know that a product has been accepted, and the police need to be alerted.

Barcode labels are usually made from coated paper, also found on normal product labels.

There are two types of barcode anti-theft adhesive labels.

  • Anti-theft adhesive labels with metal plates
  • Anti-theft adhesive labels with micro-batteries

How does the alarm go off when you Shoplift?

First of all, don’t shoplift. If you get caught, you will be reported to the police. Other than that, the security officers always monitor the customers through security cameras.

Price tags do not sound alarm because they do not have a magnet. The magnet is usually neat with the barcode and will be turned off after scanning the barcode reader.

The label on the items you bought sends a signal to the door when trying to leave the shop. If the label is not properly scanned or the tag is not deactivated, the tag signals and activates the alarms.

Many retail chains have been using these small metal bands of white anti-theft devices as a security measure to reduce theft. They are made of a material that slightly modifies the magnetic signal emitted by the detector, triggering an alarm when someone tries to walk out with items without paying.

How to prevent Security Alarms from triggering?

There is a belief that aluminum foil can prevent alarms from triggering.

A booster bag, also known as the aluminum foil bag, is a handmade bag used for shoplifting. It has several layers of aluminum foil that blocks radio signals. When the sensors are blocked, anti-theft devices cannot capture signals sent by the stolen products.

Colored security codes offer retailers an inexpensive way to have some form of security in their business. However, these ink chips will not set off an alarm if the store is broken into. Instead, they are an independent safety mechanism that may or may not alert authorities to a theft. However, an ink chip does not connect to an alarm. It is an independent safety mechanism to discourage shoplifting.

Stores don’t care too much about tightening the security to prevent people from stealing products like toffees or chocolate bars. Most small value items are not tagged with anti-theft labels.

Why do I keep setting up shop Anti Theft Alarms?

Imagine you bought your stuff from a shop, and when you’re trying to leave through the security doors, the anti-theft alarms activate. But you haven’t stolen anything. This has happened to many of us at least once in our lifetimes. Here are some instances that caused the alarm to ring.

You are wearing or taking an item with a security token that the cashier or the salesperson has not deactivated.

Gift vouchers too may activate the alarm on rare occasions.

Some merchandises have a security tag inside the item. So the only way to remove the tag is by rubbing them over a magnetic pad or electronic device.

If you are someone who has metal inside your body because of surgery or broken bones, it is more likely to set the alarm off. So if possible, always brings a doctor’s note with you.

Sometimes mobile phones, pagers, and certain car keys with a remote locking system tend to set off the alarms.

The swipe card that gives access to different parts at the workplace too is a magnetic card that activates the alarm.

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