Many goods will have bar codes, which are composed of black bars and blanks with different widths, and there will be the number 13 below. By scanning the bar code, you can know the origin, manufacturer and production date of the goods.
The numbers on the bar code can be divided into four parts. 1-3 This number belongs to the national code and is used internationally. Numbers 4-8 are manufacturers' codes, which are applied by manufacturers and allocated after national audit.
9- 12 bits belong to the commodity code, which is determined by the manufacturer, and 13 bits are the check code. As long as the bar code information is input into the computer system, you can know the product information by scanning it gently. This is a form used in the supermarket.
Besides bar codes, two-dimensional bar codes are also common. Two-dimensional bar code refers to the coding form on mobile devices. Two-dimensional bar code is composed of black and white graphics, which is not easy to imitate.
In daily life, we often meet people who let passers-by scan QR codes. This profession is also called code scanner. They often appear in busy streets and get benefits by letting others scan QR codes.
It should be noted that this form is easy to expose the owner's personal information, leading to fraud, privacy theft and other criminal acts. If this happens, you should call the police in time.