Code 128, code 128, knowledge 39, basic knowledge

128 yards, 128 yards of code knowledge

Structure of code 128
The code 128 was launched in 1981 and is a variable-length, continuous letter-and-digit bar code. Compared with other one-dimensional codes, the 128 code is a more complex bar code system, and it supports more characters than other one-dimensional codes, there are also different encoding methods available for interaction, so it is more flexible to use. The content of 128 yards is generally divided into four parts: Start code, data code, end code, and check code. The check code is dispensable. Code 128 can contain 127 characters ranging from ASCII 0 to ASCII 128. Is an example and result of code 128.

 

128 characters
Code 128 has the following features:
1. It has three different encoding types: A, B, and C. It can be used with 128 characters in standard ASCII.
2. Two-way scanning is allowed.
3. You can decide whether to add a check code.
4. The length of a bar code can be adjusted freely, but it must contain at least 232 characters and a termination code.
5. The same 128 code can be encoded in different ways. The interchange of A, B, and C encoding rules can expand the range of character selection and shorten the encoding length.

Code 128
There are three different encoding methods for the 128 code. The content of the starting code is determined by the encoding method.
Start code

Encoding type	Logical type	Relative Value
Code	11010000100	103
Code B	11010010000	104
Code C	11010011100	105

Termination code
Regardless of the encoding method A, B, and C, the termination code of the 128 code is a fixed performance, and its logic type is 1100011101011.

EAN-128 code.
Currently the implementation of 128 code is EAN-128 code, EAN-128 code is based on EAN/UCC-128 code as a standard to convert the data into a bar code symbol, and the use of 128 code logic, it features integrity, closeness, connectivity and high reliability. The Dialectical scope includes information about the performance that is easily changeable in the production process, such as the production date, batch number, and metering. It can be used for shipping tags, portable databases, continuity data segments, and distribution tags. Benefits:
1. Code-based changes in product information.
2. Common protocol standards for international circulation.
3. Better quality management for product delivery.
4. More effective control of production and distribution.
5. Provides a safer and more reliable supply source.

Code	Code difference	Length	Description
A	Application identification code	18	00 indicates that the subsequent data content is the shipping container number, which is a fixed 18-digit number.
B	Packaging performance indicator code	1	3 indicates the undefined packaging indicator code
C	Prefix code and company code	7	Represents the EAN prefix and company code
D	Self-developed serial number	9	Serial number specified by Company
E	Check Code	1	Check Code
F	Application identification code		420 indicates that the content of the subsequent documents is the delivery postal code used by only one postal authority.
G	Delivery postal code		Delivery postal code

39 yards basic knowledge

◆ 39 yards is one of the common domestic bar codes, and 39 yards is a bar code system developed in 1974 AD. There are two common causes of the Code in China. One is that the Code has few restrictions and supports text numbers. The other is that it applies to informal scenarios.
39 Code Generator: http://www.systron.com.cn/barcode.asp

◆ There is no forcible limit on the length of the Three or nine yards. As the user needs it, it can be adjusted freely. Only when planning should we take into account the limited range allowed by the bar code reader to avoid the failure to read the complete information.

◆ The data content that can be represented by three to nine codes, including: 0 ~ 9 digits, uppercase ~ Z English letters, "+", "-", "*", "/", "%", "$ 」,「., and space, a total of 44 groups of codes.

◆ In terms of reading, the reader is allowed to perform two-way scanning and reading. That is to say, if the user reversely reads the Three or nine codes, the same result is obtained.

◆ Three or nine code check codes are optional; users can use them as needed.

◆ The space occupied by codes 3 and 9 is larger than that occupied by bar codes.

◆ The start code and end code are both * characters.

39 code, 39 code

Code 39 yardsIt is a one-dimensional bar code launched by intermec in 1975,39 yardsIt is a distributed bar code that allows users to scan data in two directions,39 yardsMust contain a blank (or white, whose logical value is 0) that does not make any sense, and39 yardsSupports text numbers, simple encoding rules, low error rate, and many characters,39 yardsIt is widely used in various fields. At present, it is mainly used in industrial products, commercial materials and health care materials for hospitals. Its biggest advantage is that there is no mandatory limit on the number of codes, which can be written in uppercase and can be ignored. China has developed39 yardsNational standards (GB12908-91 ).

39 yardsThere are only two unit widths: The width unit and the narrow unit. The width of a unit is one to three times that of a narrow unit. Generally, 2 times, 2.5 times, or 3 times are used for multiple units. Each bar code character with 39 yards is composed of nine units, three of which are width units, and the rest are narrow units. Therefore, they are called three or nine codes. Code 93 Code has the same character set as 39 code, but its barcode density is higher than 39 code. Therefore, if the area is insufficient, 93 code can be used to replace 39 code.

Standard 39 yardsIt is composed of the starting security space, starting code, data code, negligible check code, ending security space, and termination code.

39-code structure features

◆ The Three or nine code components are as follows: Start code + data code + end code

◆ Illustration 1: Start code
The blue part of the bar code below is the start code.

◆ Illustration 2: Data Code
The blue part of the bar code below is the data code

◆ Illustration 3: Termination code
The blue part of the bar code below is the termination code.