General commodity bar code generally consists of prefix part, manufacturer code, commodity code and check code. The prefix code in commodity bar code is used to identify the country or region, and the code is given in ean international. For example, 00-09 stands for the United States and Canada.
45 and 49 represent Japan. 69 stands for Chinese mainland, 47 1 stands for Taiwan Province Province of China, and 489 stands for Hong Kong Special Administrative Region. The empowerment of the manufacturer code is organized by the article codes of various countries or regions, and China is given the manufacturer code by the National Article Coding Center.
Commodity code is a code used to identify commodities, and the right to assign codes is exercised by the product manufacturers themselves. At last, the 1 check code is used to check the correctness of the 1- 12 digital code from the left in the barcode.
Commodity barcode refers to a symbol composed of a group of regularly arranged bars, spaces and their corresponding characters, which is used to represent certain commodity information. Among them, the bar is dark and the space is light, which is used to scan and read bar code reading equipment.
Its corresponding characters consist of a group of Arabic numerals for people to read directly or input data to the computer through the keyboard. This set of spaces and corresponding characters represent the same information.
Extended data:
I. Coding rules
1, uniqueness: the same product with the same specification corresponds to the same product code, and the same product with different specifications should correspond to different product codes. According to the different properties of products, such as weight, packaging, specifications, smell, color, shape, etc. , give different commodity codes.
2. Permanence: Once the product code is assigned, it cannot be changed, and it is lifelong. When the product is no longer produced, its corresponding product code can only be shelved and cannot be reused and redistributed to other commodities.
3. Meaningless: In order to ensure that the code has enough capacity to meet the needs of frequent product updates, it is best to use meaningless serial codes.
Second, the principle of recognition
To convert the bar code compiled according to certain rules into meaningful information, it needs to go through two processes: scanning and decoding. The color of an object is determined by the type of light it reflects. White objects can reflect various wavelengths of visible light, while black objects absorb various wavelengths of visible light.
Therefore, when the light emitted by the light source in barcode scanner is reflected on the bar code, the reflected light shines on the photoelectric converter inside barcode scanner, and the photoelectric converter converts the reflected light signal into corresponding electrical signals according to the different intensities.
According to different principles, scanners can be divided into four types: light pen, red CCD, laser and image. The electrical signal is output to the amplification circuit of the barcode scanner to enhance the signal, and then sent to the shaping circuit to convert the analog signal into a digital signal.
The widths of white bars and black bars are different, and the duration of corresponding electrical signals is also different. The main function is to prevent the width of the dead zone from being insufficient. Then the decoder judges the number of bars and spaces by measuring the number of pulse digital electrical signals 0, 1.
The width of bars and spaces is determined by measuring the duration of 0, 1 signal. The data obtained at this time is still quite confusing. In order to know the information contained in bar code, it is necessary to convert bar code symbols into corresponding digital and character information according to the corresponding coding rules (such as EAN-8 code).
Finally, the detailed information of the article is identified by the computer system, and the data is processed and managed.
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