For example, if you check out the mineral water in this supermarket, they will use their special machine to degauss the bar code of the mineral water you want to buy, so that you won't call the police if you pass the security check. However, the mineral water you bought from a small shop (a small shop without security check) will not call the police when you bring it into the supermarket, because the information contained in the barcode indicates that this bottle of water does not belong to this supermarket, so naturally it will not call the police.
In other words, the supermarket anti-theft system detects whether payment is made through the item number information contained in the bar code magnetic strip. Barcodes are magnetic at the factory!
Two types, electronic anti-theft system in shopping malls:
There are four main anti-theft technologies for electronic articles, namely, radio frequency, electromagnetism, acoustomagnetism and radio frequency identification. Because electromagnetic and RF products are cheap, and their labels are usually permanently attached to commodities or commodity packaging; Microwave and acoustic magnetic labels are more expensive, and most supermarkets will choose electromagnetic and radio frequency. So it is explained by electromagnetism and radio frequency.
radio frequency
It is mainly composed of detector, decoder and electronic tag, and the auxiliary equipment also has a lock opener.
Electronic tags can be divided into soft tags and hard tags. Soft labels have low cost and are directly attached to "hard" goods. Soft labels cannot be reused. The one-time cost of hard label is higher than that of soft label, but it can be reused. Hard labels must be equipped with special nail puller, which is mostly used for soft and easy-to-penetrate items such as clothes. Decoders are mostly non-contact devices with a certain decoding height. When the cashier checks out or packs, the electronic tag can be decoded without touching the degaussing area. There is also a device that combines the decoder with the laser bar code scanner to complete the collection and decoding of goods at one time, which is convenient for the cashier's work.