Information technology--Automatic identification and data capture technique--Bar code symbology specifications--Code 39
Some standard content:
ICS35.040
National Standard of the People's Republic of China
GB/T 12908-2002
Replaces GB/T12908—1991
Information Technology
Automatic Identification and Data Capture Technology
Bar Code Symbol Specification
Sanjiu Bar Code
Information Technology-Automatic Identification and Data Capture Technique--Bar Code Symbologyspecifications--Code 39 (ISO/IEC16388:1999, MOD)
Published on July 18, 2002
People's Republic of China
General Administration of Quality Supervision, Inspection and Quarantine
Implementation on December 1, 2002
GB/T12908-2002
Normative referenceswwW.bzxz.Net
Terms and definitions
Symbol characteristics
Symbol structure
4.3 Character encoding
4.3.1 Symbol character encoding
4.3.2 Start and end characters
Symbol check character
Decoding algorithm
Parameters determined by application specifications
Symbol and size characteristics
Optical parameters| |tt||Allowed quality level of bar code symbols
Bar code symbol quality inspection
Width ratio N
Between bar code characters
Blank area
Appendix A (Informative Appendix)
Appendix B (Informative Appendix)
Appendix C (Informative Appendix)
Appendix D (Informative Appendix)
Additional characteristics
Guidelines for the use of the 39 bar code··
Symbol identifier
Examples of application-determining parameters
GB/T12908-2002
This standard modifies ISO/IEC16388:1999≤Information technology—Automatic identification and data acquisition technology—Bar code symbol specification—39 bar code", and revises the current national standard GB/T12908-1991 "39 bar code". This standard is based on ISO/IEC16388, and has been modified in content according to the standardization status of barcode technology in my country. The main modifications are as follows: a) According to the rules for formulating standards in my country and the relevant standards of barcode technology in my country, some text descriptions and barcode terms in this standard have been modified;
b) "4.6.3 Allowable quality level of barcode symbols" has been added to "4.6 Parameters determined by application"; c) "4.6.3 Test specification" of ISO/IEC16388 has been changed to "4.7 Barcode quality inspection". This standard replaces GB/T12908-1991 "Sanjiu Barcode". Compared with GB/T12908-1991, the main changes of this standard are as follows: a) Add the decoding algorithm of Sanjiu barcode standard; b) ISO/IEC15416 is used as the measurement specification of Sanjiu barcode; C) Some technical parameter requirements are classified as being determined by specific application specifications. Appendix A, Appendix B, Appendix C and Appendix D of this standard are all informative appendices. This standard is proposed and managed by China Article Numbering Center. The drafting unit of this standard is China Article Numbering Center. The main drafters of this standard are Liu Wei, Zhang Jingyuan and Wang Yanchun. The original version of this standard was first issued in 1991, and this is the first revision. 1 Scope
Information technology Automatic identification and data collection technology Bar code symbol specification Sanjiu bar code
GB/T12908-2002
This standard specifies the technical requirements, symbol characteristics, encoding, size and decoding algorithm of data characters of Sanjiu bar code, and lists the parameters determined by the application.
This standard applies to automatic identification and data collection. 2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For all dated referenced documents, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties to the agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all undated referenced documents, the latest versions are applicable to this standard. GB/T12905 Barcode Terminology
GB/T1988-1998 Information Technology Information Interchange Seven-bit Coded Character Set (eqVISO/IEC646:1991) GB/T17710-1999 Data Processing Check Code System idtISO7064:1983 (1996)) ISO/IEC15416 Information Technology-Automatic Identification and Data Capture Technology Barcode Printing Quality Test Specification Linear Symbols ISO/IEC15424 Information Technology-Automatic Identification and Data Capture Technology-Data Carrier/Symbol Identification 3 Terms and Definitions
The terms and definitions established in GB/T12905 apply to this standard. 4 Requirements
4.1 Symbol Characteristics
a) Encodable Character Set:
1) All alphanumeric characters from A to Z and from 0 to 9; 2) Special characters: space, $, %, ten, one,,/; 3) Start/Terminator.
The barcode type is non-continuous;
Each barcode character has 9 units, including 3 wide units and 6 narrow units, including 5 bars and 4 spaces; d)
Barcode character self-checking;
The encodable data string is non-fixed length:
Bidirectional decodable;
Symbol check characters can be selected (see Appendix A); Barcode density depends on the barcode character spacing, X size and width-to-narrow ratio N; non-data characters are equal to two symbol characters. i)
4.2 Symbol structure
The 39 barcode symbol includes: blank areas on the left and right sides, the start line, the barcode data character (including the line number check character), and the terminator, as shown in Figure 1. The barcode character spacing is a space, which separates the barcode characters. 1
GB/T12908—2002
Blank area
4.3 Character encoding
4.3.1 Symbol character encoding
Start character
See Table 1 for the character set of the Sanjiu barcode.
Figure 1 shows the Sanjiu barcode symbol of \1A\
Terminator
Blank area
4.3.2 Start character and terminator
Among the characters for human reading, the start character and terminator of the Sanjiu barcode are usually represented by *. This character cannot be used as part of the data in other positions of the symbol, and the decoder should not output it. 4.3.3 Symbol check character
The check character of the Sanjiu barcode is optional. Appendix A specifies the position and calculation method of the check character. 4.4 Size
The 39 barcode should use the following nominal sizes: Width of narrow unit (X): The X size can be determined by the application specification according to the needs of the specific application, see 4.6.1; a
Width-to-narrow ratio (N): 2.0~3.0
Width of barcode character spacing: The minimum value is X; when X<0.287mm, the maximum value is 5.3X; when X≥0.287mm, the maximum value is the larger value between 1.52mm and 3X; d) Minimum width of blank area: 10X;
For manual scanning, the recommended minimum height of the barcode is: the larger value of 5.0mm and 15% of the total length of the symbol excluding the blank area.
Note: The length W (in mm) of the 39 barcode symbol can be calculated by the following formula: W = (C+2)(3N +6)X + (C+1)I+2Q
Where: C-
Number of data characters (including symbol check characters that may be used);
Nominal size of narrow unit;
"A barcode character spacing size;
4.5 Decoding algorithm
Width of blank area.
a) Confirm the existence of blank area at the beginning.
b) For each barcode character (including start and end characters): 1) Measure the total width of 5 bars and 4 spaces, expressed as S: 2) Calculate a reading value T, T=S/8;
3) Compare the width of each unit in the character with T. If the unit width is greater than T, it is a wide unit, otherwise, it is a narrow unit; 4) Determine whether the pattern of wide and narrow units belongs to a valid character in the character set. The first barcode character must be the start or end character, which can determine the scanning direction. d) Continue to read barcode characters until all barcode characters are read! e) Confirm the existence of blank area at the end.
Note 1: * represents the start/end character
Table 1 Sanjiu barcode character set table
Note 2: B represents bar and S represents space. 0 represents a wear unit, 1 represents a wide unit B
GB/T129082002
ASCI value
GB/T12908--2002
4.6 Parameters determined by application specifications
4.6.1 Symbol and size characteristics
In application, in order to make the 39 barcode symbol suitable for printing and can be correctly read, the following symbol and size parameters need to be specified: a) Select a subset of the coded character set;
b) The number of data characters in the symbol. This number can be fixed or set as variable, or a maximum value is set for the number:
c) Whether to use the modulo 43 symbol check character (see Appendix A.1), whether the decoder outputs the symbol check character: whether to use the data check character. If used, specify its verification algorithm; d
e) X dimension range;
f) width-to-narrow ratio range N;
barcode character spacing size;
bar height minimum value.
Note 1: If you want to enhance data security in your application, you should use a symbol verification character. Note 2: In order to maximize the reading performance, try to choose a larger width-to-narrow ratio in 4.4b). Appendix D gives an example.
4.6.2 Optical parameters
In order for a barcode symbol to be correctly read in a given application, some optical parameters need to be specified. The selection of these parameters should be suitable for specific application specifications and should include the following parameters: a) Peak response wavelength; b) Half-power bandwidth of the spectrum; c) Spot size of the scanner: d) Reflectivity parameters of bars and spaces; e) Conditions required for optical measurement: 4.6.3 Allowable quality level of barcode symbols
The allowable quality level of barcode symbols is determined by the application specification. 4.7 Barcode symbol quality inspection
The barcode symbol quality inspection method adopts the test specifications in ISO/IEC15416. The ISO/IEC15416 standard allows symbol standards to establish additional pass and fail values. For the 39 barcode, 4.7.1 to 4.7.3 of this standard give such additional values. For any scanning waveform, if these conditions are not met, its quality level should be 0.
Note: The requirements in the following clauses are based on the actual values of parameter measurements rather than the theoretical values to be achieved. Therefore, it is more appropriate to use the 2 dimension (the actual size of the narrow unit) rather than the X dimension.
4.7.1 Narrowness ratio N
When the symbol is produced, the nominal value of N is between 2.0 and 3.0 (including 2.0 and 3.0). The measured value of N should be between 1.8 and 3.4 (including 1.8 and 3.4).
4.7.2 Barcode character spacing
For symbols with a Z dimension less than 0.287 mm, the maximum allowable value of the barcode character spacing is 5.32 For symbols with a Z dimension greater than or equal to 0.287 mm, the maximum value of the barcode character spacing is 3z and 1.52 mm, whichever is greater. 4.7.3 Blank Area
The minimum size of the blank area at both ends of the bar code symbol is 10Z. 4
A, 1 Check Character
A.1.1 Symbol Check Character
Appendix A
(Informative Appendix)
Additional Features
GB/T12908-2002
For applications with high data security requirements, a symbol check character should be used. In this case, this symbol check character should be immediately after the last data character and before the terminator. If a symbol check character is used, the following symbol check character algorithm should be used: a) assign a value to each data character, as shown in Table A.1; b) calculate the sum of the values of all data characters of the symbol; c) divide the sum of the values by 43;
d) the remainder value obtained in step c) corresponds to the character in Table A.1 is the symbol check character. The decoder can output a symbol check character with a modulus of 43.
Character value allocation table
GB/T12908-2002
Example: For \CODE39\data
Data character
Character value
The sum of character values
divided by 43
Character corresponding to the value 27
Data character with sign check character
A.1.2 Data check character
113+43-2-27
The 43 modulus check character can also be used as a data check character after being output by the decoder. 3
When calculating the check character, the algorithm described in the GB/T17710 standard can be selected, or the algorithm specified in the application specification can be selected. At this time, certain calculations and tests need to be added in the symbol production and information processing software. Such a data check character should be the last character of the data string and should be output by the decoder. A.2 Human-readable characters
Human-readable characters (and possible check characters) should usually be printed together with the corresponding 39 barcodes. The * indicating the start and end characters can also be printed. The size and font of the characters are not specified, but they should not occupy the blank area. The characters can be printed around the barcode symbols.
A.3 Optional data transmission mode
In order to meet the needs of specific applications, the decoder can be programmed to read non-standard 39 barcode symbols. There are three options: full ASCII code (see A.3.1), information appending (see A.3.2) and control function (see A.3.3). Since the use of these features requires special decoding programs, they should not be used in general applications to avoid mixing them with standard 39 barcode symbols. A.3.1 Full ASCII Code
The entire 128 ASCII code character set consistent with GB/T1988 can be encoded using two characters. The two characters consist of one of the four characters ($, +, %, /) and one of the 26 English letters. These combinations are shown in Table A.2. When the decoder is set to full ASCII code mode, the decoder only outputs the characters equivalent to the ASCII code after the symbol character combination, rather than outputting the literal translation of the ASCII code.
A.3.2 Information Appendage
Sometimes it is convenient to split a long message into multiple short symbols. If the first character of the 39 barcode symbol is a space, the programmed decoder will add the information after the space to a storage buffer (no data is output). This operation is used for all 39 barcode symbols that start with a space. A message is added to the end of the previous message. When the first character of the read message is not a space, the data is appended to the buffer, and then the entire message in the buffer is output, and then the buffer is cleared. At this point, the order of the data is very important, and steps should be taken to ensure that the symbols are read in the correct order. A.3.3 Control functions
has an additional system-specific mode that can be used in closed systems but not in open systems. By combining two symbol characters from the set ($, %, +, -, :, /) (ASCII values 36, 37, 43, 45, 46, 47), 36 control functions can be programmed for the system. The decoder will treat these symbols specially and execute the defined functions. The text translation of these character combinations should not be output, and the symbol identifiers (see Appendix C) should not be used. 6
ASCH code
ASCII code
Encoding code of the complete set of ASCII characters in the Sanjiu barcode
ASCII code
ASCI code
GB/T12908--2002
%T or %X or %Y or %Z
GB/T12908—2002
B.1 Compatibility of automatic identification
Appendix B
(Informative Appendix)
Guide to the use of Sanjiu barcode
Sanjiu barcode can be read by a normal barcode decoder designed to automatically identify it from other symbols. When the Sanjiu barcode and the cross-scanning 25 barcode are in the same automatic identification environment, the following guidelines should be followed: a) The nominal barcode character spacing value is X. b) The reading system should be limited, and the decoder should be programmed to ensure that the number of characters (including start and end characters) of all 39 bar code symbols is more than half of the number of characters in the interleaved 25 bar code data. c) In the same recognition environment as the 39 bar code, the number of characters of the interleaved 25 bar code is at least 6. In order to maximize the reliability of reading, the effective reading symbol set of the decoder should be limited to the symbols required in a specified application.
B.2 System Considerations
In the bar code reading system, it is very important that the various parts (printing equipment, symbol, scanner) should cooperate with each other. Any problem in any of them, or mismatch between each other, will damage the entire system. If a user or a closed system cooperation agreement specifies the scanner and bar code printing equipment, some X dimensions, the width of the bar code character interval and the spectral bandwidth can be derived from the standard values. However, the performance of the printing equipment, symbol and scanner should be matched to achieve the expected working performance.
Appendix C
Informative Appendix)
Symbol Identifier
GB/T12908—2002
Symbol identifier can be added to the decoded data as a data prefix by a programmed barcode decoder. The symbol identifier assigned by ISO/IEC15424 for the 39 barcode is: JAm
Where:
J represents the 93rd ASCII code character;
一A is the code character of the 39 barcode;
m is a modifier character, and its value is given in the following Table C.1, which represents some application and operation options. The valid values of m are: 0, 1, 3, 4, 5, 7.
Table C.1 m value and options of 39 barcode
There is no check character and no ΛSCII code set processing. All data are output as decoded. 43-module symbol check character is valid and output
43-module symbol check character is valid but not output. Perform ASCII code set conversion. No check character. Perform ASCII code set conversion. 43-module symbol check character is valid and output. Perform ASCII code set conversion. 43-module symbol check character is valid but not output. The symbol identifier should not be encoded with barcode characters, but should be generated by the decoder. After the decoder completes the decoding, this information is used as a pre-stage of data information.
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