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

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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

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17 Answers

Anonymous 0 Comments

Bar codes are only unique to the product but every RFID tag ever made has a unique code in it so each beef jerky bag has its own unique RFID code but they all have the same bar code.

When you rung it up, it pinged all the RFID tags at or very near that register and looked for an RFID tag on that product that it had not already marked as pending purchased. As you scanned the beef jerky each time, it found another one of your bags of beef jerky nearby by its unique RFID tag and added it to its list of pending purchased products. That is why they sometimes insist that you put the product in a bag as that is one area where it scans the RFID tags. When you paid, it took all the pending purchased RFID tags it scanned for your purchase and marked the list of them as purchased which made them safe for you to exit with that list of RFID tags anytime within the next few hours without setting off the alarm.

If an RFID tag that was not purchased goes past the door scanners, the alarm goes off. If you try to pay at the register and it detects an RFID tag that was not scanned, the attendant is called.

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