The concept of bar code
Barcode or barcode is a graphic identifier that arranges a plurality of black bars and blanks with different widths according to certain coding rules to represent a group of information. Common bar codes are parallel lines composed of black bars (referred to as bars) and white bars (referred to as spaces) with great differences in reflectivity. Barcode can indicate the country of production, manufacturer, commodity name, date of production, book classification number, starting and ending place, category, date and many other information, so it has been widely used in many fields such as commodity circulation, book management, postal management, banking system and so on.
[A, the history of the barcode
Bar code technology was first produced in the jittery 1920s, and was born in the laboratory of Westinghouse. John Kermode, an eccentric inventor, wanted to sort postal documents automatically in a whimsical way. At that time, every idea about the application of electronic technology was novel.
His idea is to put a barcode on the envelope, and the information in the barcode is the address of the recipient, just like today's postal code. For this reason, Comander invented the earliest bar code recognition, and the design scheme is very simple (note: this method is called modular comparison method), that is, one represents the number "1", two represents the number "2", and so on. Then, he invented a bar code reading device composed of basic components: scanner (which can emit light and receive reflected light); A method for measuring the band and space of reflected signal, namely edge positioning coil; And a method of using the measurement result, namely a decoder.
Comander's scanner uses a newly invented photovoltaic cell to collect reflected light. "Empty" reflects a strong signal, while "bar" reflects a weak signal. Unlike today's high-speed electronic components, Comander uses magnetic coils to measure "bars" and "spaces". Just like a child connecting a wire to a battery and winding it around a nail to clamp paper. Comander uses a coil with an iron core to attract the switch when it receives the "empty" signal, and release the switch when it receives the "bar" signal to connect the circuit. So the earliest bar code readers were very noisy. The switch is controlled by a series of relays, and the "on" and "off" are determined by the number of "paper strips" printed on the envelope. In this way, the bar code symbol directly sorts the letters.
Shortly thereafter, douglas young, Comand's collaborator, made some improvements to the Comand code.
Comande code contains so little information that it is difficult to compile more than ten different codes. On the other hand, Yang code uses fewer bars, but takes advantage of the change of the space between bars, just like UPC barcode symbols today use four different bar sizes. The new barcode symbol can encode 100 different regions in the same space, while Comander code can only encode 10 different regions.
It was not until 1949 that the omni-directional bar code symbols invented by Norm Woodland and Bernard Searwar were first recorded in patent documents. Prior to this, there was no record of bar code technology and no precedent for practical application. The idea of Noam Woodland and Bernard Searwar is to use the vertical "strips" and "spaces" of Comander and Yang, and bend them into rings, much like archery targets. In this way, the scanner can decode the bar code symbol by scanning the center of the graph, regardless of the direction of the bar code symbol.
In the process of perfecting this patented technology, the science fiction writer Isaac Azimov described an example of automatic identification using a new information coding method in his book The Naked Sun. At that time, people thought that the barcode symbol in this book looked like Fang Gezi's chessboard, but today's barcode professionals will immediately realize that it is a two-dimensional matrix barcode symbol. Although this bar code symbol has no direction, no positioning and no timing, it is obvious that it represents a digital code with high information density.
It was not until 1970 that ITER FACE MACHINES developed "two-dimensional code", and the printing and reading equipment of two-dimensional matrix bar code came out at a price suitable for sale. At that time, two-dimensional matrix bar code was used to realize the automation of newspaper typesetting process. Two-dimensional matrix bar code is printed on paper tape and scanned and read by today's one-dimensional CCD scanner. The light emitted by CCD shines on the paper tape, and each photocell is aimed at different areas of the paper tape. Each photovoltaic cell outputs different patterns according to whether the bar code is printed on paper tape or not, and combines them to generate high-density information patterns. In this way, a single character can be printed in the same size space as a single bar in the early Comander code. Timing information is also included, so the whole process is reasonable. When the first system entered the market, the price of the whole set of equipment including printing and reading equipment was about $5,000.
Shortly thereafter, with the continuous development of LED (light emitting diode), microprocessor and laser diode, a new symbol (symbolism) and its explosion came, which was called "barcode industry". Today, it is difficult to find companies or individuals who have not been directly exposed to fast and accurate barcode technology. With the rapid technological progress and development in this field, more and more application fields are developed every day. Before long, bar codes will be as popular as light bulbs and transistor radios, which will make everyone's life easier and more convenient.
[Edit this paragraph] 2. Bar code recognition principle
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 of the barcode scanner is reflected on the barcode, the reflected light shines on the photoelectric converter inside the barcode scanner, and the photoelectric converter converts it into corresponding electrical signals according to the reflected light signals with different intensities. According to different principles, scanners can be divided into three types: light pen, CCD and laser. 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. 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.
[Edit this paragraph] III. Advantages of barcode
1. Strong reliability. The reading accuracy of bar code far exceeds manual recording, and an error will appear every 15000 characters on average.
2. High efficiency. The reading speed of bar code is very fast, which is equivalent to 40 characters per second.
3. Low cost. Compared with other automatic identification technologies, barcode technology only needs a small sticker and a relatively simple optical scanner, and the cost is quite low.
4. Easy to make. Bar code writing is very simple, just need to print, so it is called "printable computer language".
5. Simple operation. Bar code recognition equipment is simple in structure and convenient to use.
6. Flexible and practical. Bar code symbols can be input by manual keyboard, can also be combined with related equipment to realize automatic identification, and can also be linked with other control equipment to realize automatic management of the whole system.
[Edit this paragraph] 4. Bar code scanning
The scanning of bar code needs a scanner. The scanner uses its own light source to illuminate the bar code, and then uses a photoelectric converter to receive the reflected light and convert the brightness of the reflected light into a digital signal. No matter what rules are adopted to print bar codes, they are composed of dead zones, start characters, data characters and end characters. Some barcodes also have a check character between the data character and the termination character.
▲ Quiet zone: As the name implies, an area that does not carry any information plays a prompting role.
▲ Start character: the first character with special structure. When the scanner reads this character, it begins to read the code formally.
▲ Data characters: the main content of bar code.
▲ Check the characters: check whether the read data is correct. Different coding rules may have different checking rules.
▲ Termination character: the last character, which is also a special structure, is used to inform the end of static code analysis, and also plays a role in checking calculation.
In order to facilitate bidirectional scanning, the start and stop characters have asymmetric structures. Therefore, the scanner can automatically rearrange the barcode information when scanning. There are three kinds of light pen, CCD and laser in barcode scanner.
▲ light pen: the most primitive scanning method requires manual movement of the light pen and contact with the bar code.
▲CCD: scanner with CCD as photoelectric converter and LED as light source. In a certain range, automatic scanning can be realized. And can read bar codes on various materials and uneven surfaces, and the cost is relatively low. But the scanning distance is shorter than that of the laser type.
▲ Laser: a scanner with laser as the light source. It can also be divided into linear, full angle and so on.
Linetype: mostly used for hand-held scanners, with long action distance and high precision.
All angles: mostly horizontal, with high degree of automation, which can automatically read bar codes in all directions.
[Edit this paragraph] V. Advantages of barcode technology
Bar code is by far the most economical and practical automatic identification technology. Bar code technology has the following advantages.
A. Fast input speed: Compared with keyboard input, bar code input speed is five times that of keyboard input, which can realize "instant data input".
B High reliability: the error rate of keyboard input data is 300%, the error rate of optical character recognition technology is110000, and the error rate of barcode technology is less than110000.
C. The amount of information collected is large: the traditional one-dimensional bar code can collect dozens of characters at a time, and the two-dimensional bar code can carry thousands of characters, and it has certain automatic error correction ability.
D. Flexible and practical: Bar code identification can be used as a means of identification alone, can also be combined with related identification equipment to realize automatic identification, and can also be connected with other control equipment to realize automatic management.
In addition, the bar code label is simple to make, has no special requirements for equipment and materials, and the identification equipment is simple to operate without special training, and the equipment is relatively cheap.
[Edit this paragraph] VI. Coding rules of bar code
Uniqueness: the same product with the same specification corresponds to the same product code, and different specifications of the same product 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.
Permanence: once the product code is assigned, it will not 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.
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 sequence codes.
Bar code check code formula:
1. First, sort the barcode from right to left as "... 4, 3, 2, 1." Add and sum all the numbers on even digits starting from the second serial number, multiply the calculated sum by 3, then add and sum all the numbers on odd digits starting from the third serial number, and multiply the calculated sum by the sum of the numbers on even digits. Subtract this sum by the smallest multiple larger than this sum by 10 to get the check code.
For example:
This barcode is: 977167121601x (x is the check code).
1、 1+6+2+7+ 1+7=24
2、24×3=72
3、0+ 1+ 1+6+7+9=24
4、72+24=96
5、 100-96=4
So the last check code X=4. This barcode is 9771671216014.
[Edit this paragraph] VII. Coding difference of bar code
Uniform product code
It can only indicate that there are four versions of a, b, c, d and e, version A- 12 and version E-7, and the last one is the check bit. The size is 1.5 "high 1" and the background is clear. Mainly used in the United States and Canada, used in industry, medicine, warehousing and other departments. When UPC is decoded into twelve bits, it is defined as follows: the first bit = digital identification (established by UCC (Unified Coding Committee)). Second-sixth digit = manufacturer's identification number (including the first digit) 7- 1 1 = unique manufacturer's product code 12 digits = parity bit (for error).
Code 3/9:
Can represent letters, numbers and other symbols ***43 characters: A-Z, 0-9,-. $/+%.The length of the pacing bar code can be changed. Usually "*" is used as the starting and ending symbols. The code density is 3-9.4 characters/inch, and the blank area is 10 times of the narrow strip, which is used for checking codes.
Code 128:
Represents high-density data, with variable string length and symbols containing check codes. There are three different versions: A, B and C can use 128 characters in the three string sets of A, B or C for industry, warehouse, retail and wholesale.
Staggered 2/5(I2/5):
It can only represent numbers 0 -9, variable length and continuous bar code. All bars and spaces represent codes. The first number begins with a bar, and the second number consists of spaces. The blank area is 10 times wider than the narrow strip. Used in commodity wholesale, warehouse, airport, production/packaging identification and industry. Bar codes have high recognition rate, can be used for reliable scanning of fixed scanners, and have the highest density among all one-dimensional bar codes.
Codabar (Kudba code):
It can represent the numbers 0-9, the characters $,+,-and the characters A, B and C D, and can only be used as starting and ending symbols. Its length is variable and there is no parity bit. It is used in material management, libraries, blood stations and current airport parcel delivery. The blank area is wider than the narrow column 10. It is a discontinuous bar code, and each character is represented by four bars with three spaces in the middle. Codabar, also known as NW 7, is called in Japan.
PDF4 17 (QR code):
Barcodes composed of multiple lines can store a large amount of data without connecting to a database. They can be used in hospitals, driver's licenses, material management and cargo transportation. When the bar code is damaged to a certain extent, error correction can make the bar code correctly decode PDF4 17, which is a product developed by Symbol Technology Company in 1990. It is a multi-line, continuous and variable-length symbol with a large amount of data. Each bar code has 3-90 lines, and each line has a beginning part, a data part and an end part. Its character set includes all 128 characters, and the maximum data content is 1850 characters.
One-dimensional bar code only expresses information in one direction (generally horizontal direction), and does not express any information in the vertical direction. Its height is usually for readers' alignment.
The application of one-dimensional bar code can improve the speed of information input and reduce the error rate, but it also has some shortcomings:
* Small data capacity: about 30 characters.
* can only contain letters and numbers.
* Bar code size is relatively large (low space utilization)
* The bar code cannot be read after it is damaged.
Barcodes that store information in two-dimensional space in horizontal and vertical directions are called two-dimensional barcodes.
Like one-dimensional bar code, two-dimensional bar code has many different coding methods, or coding systems. As far as the coding principles of these codes are concerned, they can usually be divided into the following three types.
1. Linear stacked QR code
Based on the principle of one-dimensional bar code coding, multiple one-dimensional codes are vertically stacked. Typical coding systems are: Code 16K, Code 49, PDF4 17, etc.
2. Matrix QR code
According to the different distribution of black and white pixels in the matrix, they are coded in rectangular space. Typical coding systems include: Aztec, Maxi code, two-dimensional code, data matrix and so on.
3. Postal code
Bar codes with different lengths are mainly used for mail coding, such as Postnet and BPO 4-State.
Among many kinds of 2D barcodes, the commonly used coding systems are: Datamatrix, Maxicode, AZTEC, QR code, Vericode, PDF 4 17, Ultra Code, Code 49, Code 16K, etc. , in which:
* The data matrix is mainly used to identify small parts in the electronics industry, such as the code printed on the back of the Intel Pentium processor.
* Maxi Code was developed by United Parcel Service (UPS) to sort and track parcels.
* Aztec is introduced by Welch Allyn Company of the United States, and can accommodate up to 3832 numbers or 3067 alphabetic characters or 19 14 bytes of data.
Next, we take PDF4 17 code as an example to introduce the characteristics and characteristics of two-dimensional code.
Introduction to 1)pdf 4 17
The code PDF4 17 was invented by Dr. Wang, a China student studying in the United States. PDF is the abbreviation of English portable data file, which means "portable data file". Because each symbol character that constitutes a bar code consists of four bars and four spaces, if the narrowest bar or space that constitutes a bar code is called a module, then the total number of modules of the above four bars and four spaces must be 17, so it is called 4 17 code or PDF4 17 code.
2) Features of PDF 417
1. Large information capacity
PDF4 17 code can represent not only letters, numbers and ASCII characters, but also binary numbers. In order to make the encoding more compact and improve the information density, PDF4 17 has three formats when encoding:
* The expanded alphanumeric compression format can accommodate 1850 characters;
* binary /ASCII format can hold 1 108 bytes;
* Digital compression format can accommodate 27 10 digits.
2. Error correction ability
One-dimensional bar codes usually have verification function to prevent misreading. Once the bar codes are defaced, they will be rejected. Two-dimensional bar code can not only prevent errors, but also correct them. Even if the bar code is partially damaged, the correct information can be recovered.
3. The printing requirements are not high
Ordinary printing equipment can print and fax can read.
You can read with all kinds of reading equipment.
PDF4 17 code can be read by laser reader with grating and image reader with linear and surface scanning.
5. The size can be adjusted to suit different printing spaces.
6. The coding system has become an international standard, and China has also formulated a national standard of 4 17 code.
3) error correction function of pdf 417.
The error correction function of two-dimensional bar code is realized by repeating (redundant) some information. For example, in the PDF4 17 code, a line contains not only the information of its own line, but also some information reflecting the characters in other positions (error correction code). In this way, even when a certain part of the bar code is damaged, its information can be recovered by error correction codes existing in other places.
The error correction capability of PDF4 17 is divided into 0~8***9 levels according to the number of error correction codes, as shown in Figure 4. The higher the level, the more correction codes, the stronger the correction ability and the larger the bar code. When the correction level is 8, even if the barcode is defaced by 50%, it can be read correctly.
4) several variants of pdf 417.
PDF4 17 also has several different coding forms:
* PDF4 17 truncation code
In a relatively "clean" environment, the bar code is less likely to be damaged, so you can omit the line indicator on the right and reduce the terminator.
* PDF4 17 microcode
Further reducing the PDF code.
* macro PDF4 17 code
When the file content is too long to be represented by PDF4 17 code, it can be represented by macro PDF4 17 code containing multiple (1~99999) barcode blocks.
Advantages of two-dimensional bar code
As can be seen from the above introduction, compared with one-dimensional bar code, two-dimensional bar code has obvious advantages, which can be summarized as follows:
1) larger data capacity.
2) Exceeding the limit of alphanumeric characters.
3) The relative size of bar code is small.
4) Have the ability to resist destruction.
[Edit this paragraph] VIII. Making bar code
Barcodes are usually printed or printed by a barcode printer. The biggest difference between bar code printer and ordinary printer is that the printing of bar code printer is based on heat, and carbon tape is used as printing medium (or thermal paper is directly used) to complete the printing. Using carbon ribbons of different materials can achieve high-quality printing effect and continuous high-speed printing without supervision.
First, application software.
Label mx
CorelDRAW
To modify (a picture or photograph) with a computer.
Illustrator
Label mx is a professional bar code generation and printing software, which integrates bar code generation, drawing design, label making and batch print, and can print fixed and variable data. CorelDRAW, Photoshop and Illustrator are professional drawing design software; In addition, Label mx can export barcodes as vector pictures (. The sum of electromotive force. Wmf) and interact with CorelDRAW, Photoshop and Illustrator.
[Edit this paragraph] 9. Commodity bar code:
EAN- 13 general commodity bar code generally consists of prefix, 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. 45-49 stands for Japan. 690-692 stands for Chinese mainland, 47 1 stands for Taiwan Province Province and 489 stands for Hong Kong Special Administrative Region. The empowerment of manufacturers' codes is organized by article codes in various countries or regions, while in China, the National Article Coding Center gives manufacturers' codes. Commodity codes are codes used to identify commodities, and the right to assign codes is exercised by the product manufacturers themselves. Manufacturers themselves decide which Arabic numerals to use for their products according to the prescribed conditions. At last, the 1 parity code is used to check the correctness of the L- 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 empty, which is a reading device used to scan and read bar codes. 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.
Bar code technology was born with the development and application of computer and information technology. It is a new technology integrating coding, printing, identification, data acquisition and processing.
Using bar code scanning is the general trend of future market circulation. In order to make goods circulate freely and widely in the world, enterprises must abide by the relevant provisions of commodity bar codes whether designing, manufacturing, applying for registration or using commodity bar codes.
At present, ENA barcode, UPC barcode, 25 barcode, cross barcode, Kudba barcode, Sanjiu barcode and 128 barcode are commonly used in the world, among which EAN barcode is the most commonly used commodity.
EAN commodity bar code, also known as general commodity bar code, is formulated by ean international and is widely used in the world. It is the most widely used commodity bar code in the world. At present, this commodity bar code is being used in China. EAN commodity bar codes are divided into EAN- 13 (standard version) and EAN-8 (abbreviated version).
The coding of commodity bar codes follows the principle of uniqueness, so as to ensure that commodity bar codes will not be repeated in the global scope, that is, a commodity item can only have one code, or a code can only identify one commodity item. Commodities with different specifications, different packages, different varieties, different prices and different colors can only use different commodity codes.
The standard size of commodity bar code is 37.29mmx26.26mm, and the magnification is 0.8-2.0. When the printing area allows, the barcode with magnification of 1.0 should be selected to meet the reading requirements. The smaller the magnification, the higher the printing accuracy. When the printing accuracy can not meet the requirements, it is easy to read the bar code.
Because the identification of bar code is realized by the color contrast between bar code and blank bar code, generally speaking, as long as the color can meet the requirements of contrast (PCS value), light color can be used as blank color, such as white, orange and yellow, and dark color as bar, such as black, dark green and dark brown. The best color scheme is black stripes and white spaces. According to the practical experience of bar code detection, red, gold and light yellow should not be used as bar code colors, and transparent and gold should not be used as blank colors.
EAN-8 commodity bar code refers to the 8-digit commodity bar code used for identification, which consists of 7-digit commodity item code and 1 digit check code.
The birth of commodity bar code greatly facilitates the circulation of commodities, and modern society cannot do without commodity bar code. According to statistics, at present, there are 500,000 kinds of products in China that use the international commodity bar code. After China's entry into WTO, enterprises will surely win more space for activities on the international stage. To keep up with international practice and meet the needs of international trade, enterprises should not mistreat commodity bar codes.
Country/Prefix Code Organization Application Field Country/Prefix Code Organization Application Field
000 ~ 0 19; 030 ~ 039; 060 ~ 139 USA
020 ~ 029; 040 ~ 049; 200 ~ 299 in-store code
050 ~ 059 coupon
300 ~ 379 France
380 Bulgaria
383 Slovenia
385 Croatia
387 Bosnia and Herzegovina
400 ~ 440 Germany
450 ~ 459; 490 ~ 499 Japan
460 ~ 469 Russia
470 Kyrgyzstan
47 1 Taiwan Province Province, China
Estonia
Latvia
476 Azerbaijan
Lithuania
478 Uzbekistan
479 Sri Lanka
480 Philippines
48 1 Belarus
Ukraine
Moldova
485 Armenia
486 Georgia
487 Kazakhstan
489 China Special Administrative Region
500 ~ 509 England
520 Greece
528 Lebanon
529 Cyprus
530 Albania
53 1 Macedonia
535 Malta
539 Ireland
540 ~ 549 Belgium and Luxembourg
560 Portugal
569 Iceland
570 ~ 579 Denmark
590 Poland
Romania
599 Hungary
600,601South Africa
603 Ghana
608 Bahrain
609 Mauritius
6 1 1 Morocco
6 13 Algeria
6 16 Kenya
6 18 ivory coast
6 19 Tunisia
62 1 Syria
Egypt
Libya
625 Jordan Street
Iran
627 Kuwait
628 Saudi Arabia
629 United Arab Emirates
640 ~ 649 Finland
690 ~ 695 People's Republic of China (PRC)
700 ~ 709 Norway
729 Israel
730 ~ 739 Sweden
740 Guatemala
74 1 El Salvador
Honduras
Nicaragua
Costa Rica
Panama 745
746 Dominica
750 Mexico
754 ~ 755 Canada
759 Venezuela
760 ~ 769 Switzerland
770 Colombia
773 Uruguay
775 Peru
777 Bolivia
779 Argentina
780 Chile
Paraguay
786 Ecuador
789 ~ 790 Brazil
Italy from 800 to 839
840 ~ 849 Spain
850 Cuba
Slovakia
859 Czech
860 Yugoslavia
865 Mongolia
867 Korea
869 Turkey
870 ~ 879 Holland
880 Korea
884 Cambodia
885 Thailand
888 Singapore
890 India
893 Vietnam
Indonesia
900 ~ 9 19 Austria
930 ~ 939 Australia
940 ~ 949 New Zealand
955 Malaysia
958 China Special Administrative Region
977 serial publications
978,979 books
980 notes receivable
98 1, 982 general circulation voucher
990 ~ 999 coupon
[Edit this paragraph] X. Requirements for printing bar codes
The standard size of commodity bar code is 37.29mm x 26.26mm, and the magnification is 0.8-2.0. When the printing area allows, the barcode with magnification of 1.0 should be selected to meet the reading requirements. The smaller the magnification, the higher the printing accuracy. When the printing accuracy can not meet the requirements, it is easy to read the bar code.
Because the identification of bar code is realized by the color contrast between bar code and blank bar code, generally speaking, as long as the color can meet the requirements of contrast (PCS value), light color can be used as blank color, such as white, orange and yellow, and dark color as bar, such as black, dark green and dark brown. The best color scheme is black stripes and white spaces. According to the practical experience of bar code detection, red, gold and light yellow should not be used as bar code colors, and transparent and gold should not be used as blank colors.
Eleven, the meaning of commodity bar code number
Take the barcode 69369838000 13 as an example.
The bar code is divided into four parts from left to right:
1-3 digits: * * 3 digits, corresponding to bar code 693, which is one of the national codes of China. (690-695 are all codes of China, which are allocated internationally);
4-8 digits: * * * 5 digits, corresponding to barcode 69838, representing the manufacturer's code, which is applied by the manufacturer and allocated by the state;
9- 12 digits: * * 4 digits, corresponding to barcode 000 1, representing the commodity code in the factory, which is determined by the manufacturer;
13: * * *1,corresponding to 3 of the barcode, is a check code, which is calculated by the previous 12 bits according to a certain algorithm.