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In recent years, the rapid development of science and technology networks has led to the vigorous development of the QR code industry. The wide application of QR codes has brought great convenience to people’s daily lives, and it’s easy to scan wherever you go. , Quickly solve various problems of food, clothing, housing and transportation. Therefore, two-dimensional codes are widely used in various industries, and many companies have begun to pay more and more attention to the use and management of two-dimensional codes. The assignment of two-dimensional codes to products can not only achieve product traceability, but also help manufacturing companies trace their roots. , Eliminate counterfeit products and counterfeit goods, but also protect brand value.
Today, we will give a detailed explanation of the Code128, QR code, and DM codes that are frequently used by our partners, so that you can better understand the coding capabilities of agile logos. We also hope to help you when you design related solutions.
Code128
CODE128 is a high-density bar code introduced in 1981. CODE128 code can represent a total of 128 characters from ASCII0 to ASCII127, so it is called code 128. It contains numbers, letters and symbol characters. It is widely used in the bar code system of enterprise internal management, production process, logistics control system, and is widely used in the design of management information system due to its excellent characteristics.
Features
· Can express high-density data and character strings;
·Each character is composed of 3 bars, 3 spaces, and 11 units, and the character string can be variable length;
·The symbol contains a check code;
·There are three different versions: A (numbers, uppercase letters, control characters) B (numbers, uppercase and lowercase letters, characters) C (double digits)
CODE128A: standard numbers and uppercase letters, control characters, special characters
CODE128B: standard numbers and uppercase letters, lowercase letters, special characters
CODE128C: [00]-[99] set of number pairs, a total of 100
· 128 characters are available in the three character strings A, B or C.
From left to right are black and white barcodes, the black one is called "bar" (B), and the white one is called "empty" (S).
If you look closely, the bars and spaces have 4 different widths. We assign the values 1, 2, 3, and 4 from fine to coarse.
We started to read the barcode according to the thickness value, and the results are as follows:
211232|112232|131123|331121|241112|214121|112232|311123|2331112
Note that this result is black and white, with a total of 55 digits.
Code128 has a head, a check, and a tail.
The tail is always 2331112, which means that Code128 has ended. The remaining part is 6 bits as a block.
The header of Code128 has three specifications
Type A: 211412
Type B: 211214
Type C: 211232
We remove the beginning and end of the above Code128 code and re-divide to get:
112232|131123|331121|241112|214121|112232|311123
It is exactly 6 digits as a block. We can remove the last block (check digit) of the tail section, which is used to check whether the barcode is correctly encoded, and then corresponds to the Code128 character table. This string of codes starts with 211232 and belongs to Code128C type. Type C codes are pure numbers, and each block corresponds to 2 digits.
Look up the table to get 12, 34, 56, 78, 90, 12.
QR code
QR code is a type of two-dimensional bar code. QR comes from the abbreviation of "Quick Response" in English, which means quick response. It originated from the inventor's hope that the QR code could enable its content to be decoded quickly. The QR code is square and only has black and white. Three of the four corners are printed with smaller square patterns like "Hui". The three corners are the patterns that help the decoding software to locate. The user does not need to align, and the data can still be read correctly regardless of scanning at any angle.
Features
·Large storage capacity
The traditional bar code can only process about 20 digits of information. In contrast, the QR code can process dozens of times or hundreds of times the information. In addition, QR codes can also support all types of data (such as: numbers, English letters, Japanese letters, Chinese characters, binary, control codes, etc.). A QR code can handle a huge amount of information of up to 7089 digits.
·Small space
QR codes use vertical and horizontal directions to process data. With the same amount of information, the QR code occupies a smaller space. I first draw the graph on the screen, then use the scanner to scan, and then reduce the graph until the scanner can’t recognize it. Finally, zoom in in equal proportions to get the comparison of the area drawn below.
·Strong error correction ability
QR code has "error correction function", even if part of the code becomes dirty or damaged, the data can be restored. Data recovery is based on codewords (it is the unit that constitutes internal data. In the case of QR codes, every 8 bits represents 1 codeword), and the error correction can be up to about 30% (depending on the degree of dirty and damaged, there are also Unrecoverable situation).
·Can be read from any direction
The QR code can be quickly read from any direction of 360°. There are 3 positioning patterns in the QR code, which can help the QR code not be affected by the background style and achieve fast and stable reading. When scanning barcodes with traditional laser scanners, only one direction can be used for scanning, but if a CCD scanner is used, barcodes can be scanned from any direction.
DM code
The DM code was invented by the International Data Matrix (IDMatrix) in 1989 and has the international ISO standard. DataMatrix code is a matrix type two-dimensional bar code, its biggest feature is high density, and its smallest size is the smallest code among all current bar codes. The DM code can encode 30 numbers on an area of only 25mm. DM adopts complex error correction code technology, which makes the code has super anti-pollution ability. Because Datamatrix provides extremely small and high-density labels, and can still store reasonable data content, it is especially suitable for small parts identification, product anti-counterfeiting, circuit identification, etc. Due to its excellent error correction ability, DM code has become the mainstream technology of brand mobile phone two-dimensional bar code.
