1、BRITISH STANDARDBS ISO/IEC 15417:2007Information technology Automatic identification and data capture techniques Code 128 bar code symbology specificationICS 01.080.50; 35.040g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3
2、g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS ISO/IEC 15417:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 June 2007 BSI 2007ISBN 978 0 580 56258 7National forewordThis British Standard was published by
3、 BSI. It is the UK implementation of ISO/IEC 15417:2007. It supersedes BS ISO/IEC 15417:2000 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee IST/34, Automatic identification and data capture techniques.A list of organizations represented on this commit
4、tee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publica
5、tionAmd. No. Date CommentsReference numberISO/IEC 15417:2007(E)INTERNATIONAL STANDARD ISO/IEC15417Second edition2007-06-01Information technology Automatic identification and data capture techniques Code 128 bar code symbology specification Technologies de linformation Techniques didentification auto
6、matique et de capture des donnes Spcifications des symbologies des codes barres, code 128 BS ISO/IEC 15417:2007ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Requirements 2 Annex A (normative) Additional features of Code 128. 15 Ann
7、ex B (normative) Special considerations relating to Function Code 1 (FNC1). 16 Annex C (normative) Symbology identifiers . 18 Annex D (informative) Relationship of symbol character value to ASCII value. 19 Annex E (informative) Use of Start, Code Set and Shift characters to minimize symbol width. 20
8、 Annex F (informative) ISO/IEC 8859-1 (Latin Alphabet no. 1) character set. 21 Annex G (informative) User-defined application parameters 22 Annex H (informative) Guidelines for the use of Code 128 23 Bibliography . 25 BS ISO/IEC 15417:2007iv Foreword ISO (the International Organization for Standardi
9、zation) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization
10、to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO
11、and IEC have established a joint technical committee, ISO/IEC JTC 1. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of the joint technical committee is to prepare International Standards. Draft International Standards adopted b
12、y the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of pate
13、nt rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. ISO/IEC 15417 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 31, Automatic identification and data capture techniques. This second edition cancels and
14、 replaces the first edition (ISO/IEC 15417:2000), which has been technically revised. BS ISO/IEC 15417:2007vIntroduction The technology of bar coding is based on the recognition of patterns encoded in bars and spaces of defined dimensions. There are numerous methods of encoding information in bar co
15、de form, known as symbologies. Code 128 is one such symbology. The rules defining the translation of characters into bar and space patterns, and other essential features of each symbology, are known as the symbology specification. In the past, symbology specifications were developed and published by
16、 a number of organizations, resulting in certain instances in conflicting requirements for certain symbologies. Manufacturers of bar code equipment and users of bar code technology require publicly available standard symbology specifications to which they can refer when developing equipment and soft
17、ware. BS ISO/IEC 15417:2007blank1Information technology Automatic identification and data capture techniques Code 128 bar code symbology specification 1 Scope This International Standard specifies the requirements for the bar code symbology known as Code 128. It specifies Code 128 symbology characte
18、ristics, data character encodation, dimensions, decoding algorithms and the parameters to be defined by applications. It specifies the symbology identifier prefix strings for Code 128 symbols. 2 Normative references The following referenced documents are indispensable for the application of this doc
19、ument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO/IEC 646:1991, Information technology ISO 7-bit coded character set for information interchange ISO/IEC 8859-1, Information techno
20、logy 8-bit single-byte coded graphic character sets Part 1: Latin alphabet No. 1 ISO/IEC 15416, Information technology Automatic identification and data capture techniques Bar code print quality test specification Linear symbols ISO/IEC 15424, Information technology Automatic identification and data
21、 capture techniques Data Carrier Identifiers (including Symbology Identifiers) ISO/IEC 19762-1, Information technology Automatic identification and data capture (AIDC) techniques Harmonized vocabulary Part 1: General terms relating to AIDC ISO/IEC 19762-2, Information technology Automatic identifica
22、tion and data capture (AIDC) techniques Harmonized vocabulary Part 2: Optically readable media (ORM) 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO/IEC 19762-1 and ISO/IEC 19762-2 apply. BS ISO/IEC 15417:20072 4 Requirements 4.1 Symbology characteri
23、stics The characteristics of Code 128 are as follows. a) Encodable character set: 1) All 128 ISO/IEC 646 characters, i.e. characters 0 to 127 inclusive, in accordance with ISO/IEC 646. NOTE This version consists of the G0 set of ISO/IEC 646 and the C0 set of ISO/IEC 6429 with values 28 31 modified t
24、o FS, GS, RS and US respectively. 2) Characters with byte values 128 to 255 may also be encoded. 3) 4 non-data function characters. 4) 4 code set selection characters. 5) 3 Start characters. 6) 1 Stop character. b) Code type: Continuous. c) Elements per symbol character: 6, comprising 3 bars and 3 s
25、paces, each of 1, 2, 3 or 4 modules in width (Stop character: 7 elements comprising 4 bars and 3 spaces). d) Character self-checking: Yes. e) Symbol length: Variable. f) Bidirectionally decodable: Yes. g) Symbol check character: One, mandatory (see A.1). h) Data character density: 11 modules per sym
26、bol character (5,5 modules per numeric character). i) Non-data overhead: Equivalent to 35 modules. 4.2 Symbol structure Code 128 symbols shall comprise a) a leading quiet zone, b) a Start character, c) one or more characters representing data and special characters, d) a symbol check character, e) a
27、 Stop character, f) a trailing quiet zone. Figure 1 illustrates a Code 128 symbol encoding the text “AIM”. BS ISO/IEC 15417:20073Quiet zone Start char. Data characters Symbol Stop char. Quiet Zone check char. AIMFigure 1 Code 128 symbol 4.3 Character encodation 4.3.1 Symbol character structure Each
28、symbol character comprises six elements (three bars and three spaces arranged alternately from left to right, commencing with a bar), each of which is 1, 2, 3 or 4 modules wide, with a total width of 11 modules. The sum of the bar modules in any symbol character is always even (even parity) and that
29、 of the space modules is therefore always odd. This parity feature enables character self-checking to be carried out. The Stop character comprises an additional bar element two modules wide making its total width 13 modules. Each symbol character is assigned a numeric value listed in Table 1. This v
30、alue is used in calculating the symbol check character value. It may also be used to provide a conversion to and from ISO/IEC 646 values (see Annex D). Table 1 defines all the Code 128 character assignments. In the column headed Element Widths the numeric values represent the widths of the elements
31、in modules or multiples of the X dimension. Figure 2 below illustrates Start character A. 1 2 3 4 5 6 7 8 9 10 11 2 1 14 12 Figure 2 Code 128 Start character A Figure 3 below illustrates the encodation of the symbol character value 35, which represents data character C in Code Sets A or B or the two
32、 digits 35 in Code Set C. 1 2 3 4 5 6 7 8 9 10 11 1 3 13 2 1Figure 3 Code 128 symbol character value 35 BS ISO/IEC 15417:20074 Figure 4 below illustrates the Stop character. 1 2 3 4 5 6 7 8 9 10 11 12 13 2 3 3 1112 Figure 4 Code 128 Stop character 4.3.2 Data character encodation Code 128 has three u
33、nique data character code sets shown in Table 1 as Code Sets A, B, and C, each comprising a subset of the ISO/IEC 646 IRV character set together with various auxiliary characters. The symbol character bar and space patterns shown represent the data characters listed in the columns for Code Set A, B,
34、 or C. The choice of code set depends on the Start character or, within the symbol, on the use of Code A, Code B or Code C characters or the Shift character. If the symbol begins with Start character A, then Code Set A is defined initially. Code Set B and Code Set C are similarly defined by beginnin
35、g the symbol with Start character B or C respectively. The code set can be redefined within the symbol by the use of Code A, Code B, and Code C characters or the Shift character (see 4.3.4.1 for the use of these special characters). The same data may be represented by different Code 128 symbols, thr
36、ough the use of different combinations of Start, Code Set, and Shift characters. An application should not specify the code set to be used. Annex E contains rules to minimize the length of the symbol for any given data. A decoder shall in addition decode symbols which use valid combinations of Start
37、, Code Set, and Shift characters and data other than that derived from the application of the algorithm in Annex E, such as a symbol with a code set or Shift character at the end of the data. Table 1 Code 128 character encodation SYMBOL CHAR. VALUE CODE SET A ISO/IEC 646 VALUE for Set A CODE SET B I
38、SO/IEC 646 VALUE for Set B CODE SET C ELEMENT WIDTHS (modules) ELEMENT PATTERN B S B S B S 1 2 3 4 5 6 7 8 9 10 110 space 32 space 32 00 2 1 2 2 2 2 1 ! 33 ! 33 01 2 2 2 1 2 2 2 “ 34 “ 34 02 2 2 2 2 2 1 3 # 35 # 35 03 1 2 1 2 2 3 4 $ 36 $ 36 04 1 2 1 3 2 2 5 % 37 % 37 05 1 3 1 2 2 2 6 C is the numbe
39、r of symbol characters (including symbol check character ); X is the width of a narrow element in millimetres; Q is the width of the quiet zone in millimetres. NOTE It is necessary to apply the rules in Annex E, or another algorithm, to determine the number of symbol characters before this expressio
40、n can be evaluated. 4.5 Reference decode algorithm Bar code reading systems are designed to read imperfect symbols to the extent that practical algorithms permit. This section describes the reference decode algorithm used in the computation of the decodability value described in ISO/IEC 15416. The a
41、lgorithm contains the following steps to decode each bar coded character. 1. Calculate eight width measurements p, e1, e2, e3, e4, b1, b2, and b3(Figure 5). Figure 5 Decode measurements BS ISO/IEC 15417:200710 2. Convert measurements e1, e2, e3, and e4to normalized values E1, E2, E3, and E4which wil
42、l represent the integral module width (Ei) of these measurements. The following method is used for the i-th value. If 1,5p / 11 ei 2,5p / 11, then Ei= 2. If 2,5p / 11 ei 3,5p / 11, then Ei= 3. If 3,5p / 11 ei 4,5p / 11, then Ei= 4. If 4,5p / 11 ei 5,5p / 11, then Ei= 5. If 5,5p / 11 ei 6,5p / 11, th
43、en Ei= 6. If 6,5p / 11 ei 7,5p / 11, then Ei= 7. Otherwise the character is in error. 3. Look up character in decode table using the four values E1, E2, E3, and E4as the key. (See Table 2.) 4. Retrieve character self-checking value V which is stored in the table with the character. The value V is eq
44、ual to the sum of the modules for the bars as defined for that character. 5. Verify that ( )()( )1231, 7 5 1, 7 511 11+Vp Vpbb b Otherwise the character is in error. The calculation indirectly uses character parity to detect all decode errors caused by single non-systematic one-module edge errors. U
45、sing these five steps, decode the first character. If it is a Start character, continue decoding the symbol in the normal forward direction. If it is not a Start character but decodes as a Stop character, attempt to decode all subsequent characters in the reverse direction. After all characters have
46、 been decoded, make sure there is a valid Start character, a valid Stop character, and that the symbol check character is correct. Translate the symbol characters into the appropriate data characters from Code Set A, B, or C according to the Start character, code characters, and shift characters use
47、d in the symbol. In addition, perform such other secondary checks on quiet zones, beam acceleration, absolute timing, dimensions, etc., as are deemed prudent and appropriate considering the specific reading device and intended application environment. NOTE In this algorithm the symbol is decoded usi
48、ng “edge to similar edge“ measurements (e), plus an additional measurement of the sum of the three bar widths. Table 2 Edge differences for decoding Code 128 Char. value E1E2E3E4V Char. value E1E2E3E4V 0 3 34 4 6 54 4223 6 01 4 43 3 6 5 4245 6 02 4 44 4 6 56 6423 6 03 3 33 4 4 57 4332 6 04 3 34 5 4
49、58 4354 6 05 4 43 4 4 59 6532 6 BS ISO/IEC 15417:200711Char. value E1E2E3E4V Char. value E1E2E3E4V 06 3 4 4 3 4 60 4 5 5 2 807 3 4 5 4 4 61 4 3 5 5 408 4 5 4 3 4 62 7 4 2 2 609 4 3 3 3 4 63 2 2 3 4 410 4 3 4 4 4 64 2 2 5 6 411 5 4 3 3 4 65 3 3 2 3 412 2 3 4 5 6 66 3 3 5 6 413 3 4 3 4 6 67 5 5 2 3 414 3 4 4 5 6 68 5 5 3 4 415 2 4 5 4 6 69 2 3 4 3 416 3 5 4 3 6 70 2 3 6 5 417 3 5 5 4 6 71 3 4 3 2 418 4 5 5 3 6 72 3 4 6 5 419 4 3 2 4 6 73 5 6 3 2 420 4 3 3 5 6 74 5 6
