So what's the use of bar codes? Why do commodities, books and periodicals use bar codes? Bar code is actually a new information technology-bar code technology, which is produced with the development of computer technology and the expansion of economic exchanges. It can collect and transmit information most economically, quickly and accurately. Simply put, the purpose of bar codes is to convey information.
Isn't it incredible that some vertical bars with different widths can convey information? Here is a brief introduction. Barcodes can convey information because they represent certain information. This information of the barcode can be read by the machine. Barcodes express different information through bars and spaces with different widths and arrangements. If you carefully observe several different bar codes, you will find that although they look similar on the surface, they are definitely slightly different. These small differences to our naked eyes are huge differences in computers, because computers convert them into a series of binary numbers. As we know, in the binary system, there are only two numbers, 0 and 1, and these two numbers can be distinguished by the width and narrowness of the bar code. The computer recognizes bar codes through photoelectric reading devices such as light pens. When the light shines on the bar code, there is a strong contrast between the black bar and the blank, which can be converted into different currents, and the width of the bar and the blank can cause the signal to appear for a long time, which can be directly recognized by the computer. Usually, bar codes are also readable in both directions, that is, they can be scanned and read from the left and right sides. This is because the decoder will automatically determine the scanning direction during reading.
Since bar codes are characters recognized by machines, is it impossible for people to recognize them? In fact, considering that optical characters or human eyes can be used to identify problems in bar code reading equipment, characters for human identification are added to various bar codes, which can make people have a general understanding of the information represented by bar codes. Therefore, bar codes usually consist of a set of regularly arranged bars, spaces and their corresponding characters. According to the appearance characteristics of bar codes abroad, they are called bar codes, cosmic rays, zebra crossings and so on.
Since bar codes transmit information through computers, there should be a unified code. For example, the automobile industry chooses Code39, which is the logo specification of the automobile industry stipulated by AIAG and plays a certain technical guiding role in the world automobile industry. In order to adapt to the exchange and development of automobile industry in various countries in the world, this specification is formulated. Many industries or groups in the world have stipulated their own bar code usage norms. Of course, there are also some bar code management systems that are limited to a certain unit, such as large shopping supermarkets, so this system does not have to meet the general specifications.
With the popularization of computer technology, as the only machine language that can print directly, the application scope of bar code will be more extensive.