Eli5: how do anti theft radio frequency tags know i bought an item

Question

for context i just bought 3 bags of beef jerky from 5 below and they all had one of those square tags with the lines on them and i only scanned one 3 times at the self checkout how do they get deactivated

Edit [https://imgur.com/a/c3DFJFg](https://imgur.com/a/c3DFJFg) here’s a picture of it

In: Other

Answer 1

RFID tags are inventory devices and not generally for anti theft. If the store has a device capable of reading RFID tags, it’s like playing Marco-Polo. These devices can do one of two things: count product or find product. The RFID has a unique code, a voice if you will, depending on the UPC code and other embedded coding unique to that one item (like a name).

For instance, if I’m looking for my Slim Jim’s, I’ll tell the device what item code I’m looking for. The device starts sending out a signal and looking for the match of just the UPC. Imagine it saying ‘Marco!’ constantly until it picks up on the familiar voice, ‘Polo!’ Some of these devices make a variety of sounds, usually more frequently sounds, as you get closer to the product you are searching for.

For inventory reasons, the device may not make many sounds, but is sending out constant ‘Marco!’s and receiving a variety of ‘Polo!’s back to it. The device is then tallying up each unique voice it hears along with those unique names. After some time the operator of the device finishes waving this device around a store and a computer handles the data to determine what is still in the store versus what the store should actually have. For instance, I should have 20 Slim Jim’s but my device may only picked up 18. For inventory management, it sees I have a discrepancy, a loss, of two. But I also have data containing how many pillows in the store, laundry detergent, etc.

These inventories then be put together to find other statistics that could be effecting a store, like theft or operational shortages. These inventories can also be used to correct systems data in which stores use to order more products if none of these particular voices are heard yet they are supposed to exist.

Along with these inventories, the system sees that your three slim Jim’s are scanned and corrects the count for what the store should have prior to the next inventory sweep with the device just through the UPC code. The RFID has nothing to do with the register or scanner once it’s at a checkout.

Anything that sets off EAS towers are anti theft deterrents that generally are using magnetic sensors- no RFID included.