1、BRITISH STANDARD BS ISO/IEC 16390:2007 Information technology Automatic identification and data capture techniques Interleaved 2 of 5 bar code symbology specification ICS 01.080.50; 35.040 BS ISO/IEC 16390:2007 This British Standard was published under the authority of the Standards Policy and Strat
2、egy Committee on 31 July 2007 BSI 2007 ISBN 978 0 580 56256 3 National foreword This British Standard is the UK implementation of ISO/IEC 16390:2007. It supersedes BS ISO/IEC 16390:1999 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee IST/34, Automatic
3、 identification and data capture techniques. A list of organizations represented on this committee 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
4、a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. Date Comments Reference number ISO/IEC 16390:2007(E)INTERNATIONAL STANDARD ISO/IEC 16390 Second edition 2007-06-15 Information technology Automatic identification and data capture technique
5、s Interleaved 2 of 5 bar code symbology specification Technologies de linformation Techniques didentification automatique et de capture des donnes Spcifications des symbologies des codes barres, code 2 parmi 5 entrelac BS ISO/IEC 16390:2007ii iii Contents Page Foreword iv Introduction v 1 Scope 1 2
6、Normative references 1 3 Terms and definitions .1 4 Requirements.1 4.1 Symbology characteristics .1 4.2 Symbol structure .2 4.3 Character encodation2 4.4 Dimensions.5 4.5 Reference decode algorithm 6 4.6 Symbol quality .6 4.7 Application-defined parameters.7 Annex A (informative) Additional features
7、 .9 Annex B (informative) Guidelines for the use of Interleaved 2 of 5 .11 Annex C (normative) Symbology identifier 14 Annex D (informative) Examples of application-defined parameters 15 Bibliography 17 BS ISO/IEC 16390:2007iv Foreword ISO (the International Organization for Standardization) and IEC
8、 (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 to deal with pa
9、rticular 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 and IEC have es
10、tablished 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 by the joint tec
11、hnical 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 patent rights. ISO
12、and IEC shall not be held responsible for identifying any or all such patent rights. ISO/IEC 16390 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 replaces the f
13、irst edition (ISO/IEC 16390:1999), which has been technically revised. BS ISO/IEC 16390:2007v Introduction 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 code form, known
14、 as symbologies. Interleaved 2 of 5 is one such symbology. The rules defining the translation of characters into bar and space patterns and other essential features are known as the symbology specification. In the past, symbology specifications were developed and published by a number of organizatio
15、ns, 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 application standards. BS IS
16、O/IEC 16390:2007 blank1 Information technology Automatic identification and data capture techniques Interleaved 2 of 5 bar code symbology specification 1 Scope This International Standard specifies the requirements for the bar code symbology known as Interleaved 2 of 5; it specifies Interleaved 2 of
17、 5 symbology characteristics, data character encodation, dimensions, tolerances, decoding algorithms and parameters to be defined by applications. It specifies the Symbology Identifier prefix strings for Interleaved 2 of 5 symbols. 2 Normative references The following referenced documents are indisp
18、ensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 646, Information technology ISO 7-bit coded character set for information interchange ISO/
19、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 capture techniques Data carrier identifiers (including Symbology Identifiers) ISO/IE
20、C 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 identification and data capture (AIDC) techniques Harmonized vocabulary Part 2: Optically reada
21、ble 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. 4 Requirements 4.1 Symbology characteristics The characteristics of Interleaved 2 of 5 are: a) Encodable character set: numeric 0 to 9 (ASCII chara
22、cters 48 - 57 inclusive, in accordance with ISO/IEC 646); b) Code type: continuous; BS ISO/IEC 16390:20072 c) Elements per symbol character: 5, of which 2 wide and 3 narrow, encoded as either five bars or five spaces; d) Character self-checking: yes; e) Data string length encodable: variable (even n
23、umber of digits); f) Bidirectionally decodable: yes; g) Symbol check character: one, optional (see annex A); h) Symbol character density: 14 to 18 modules per symbol character pair, depending on wide/narrow ratio; i) Non-data overhead: 8 to 9 modules, depending on wide/narrow ratio. 4.2 Symbol struc
24、ture Interleaved 2 of 5 symbols shall comprise: a) leading quiet zone; b) start pattern; c) one or more pairs of symbol characters representing data (inclusive of optional symbol check character); d) stop pattern; e) trailing quiet zone. 4.3 Character encodation 4.3.1 Symbol character structure Data
25、 is encoded as interleaved pairs of symbol characters, the first of which comprises two wide and three narrow bars and the second of which comprises two wide and three narrow spaces, the first bar of the first character being followed by the first space of the second character, then the second bar o
26、f the first character and the second space of the second character, and so on until the last space of the second character, which is directly followed by the first bar of the next symbol character pair (or stop pattern). 4.3.2 Data character encodation Table 1 defines the Interleaved 2 of 5 characte
27、r encodation. In the columns headed “Binary representation“ the character 1 is used to represent a wide element and 0 a narrow element. BS ISO/IEC 16390:20073 Table 1 Binary representation of character encodation Data character Binary representation 0 0 0 1 1 0 1 1 0 0 0 1 2 0 1 0 0 1 3 1 1 0 0 0 4
28、0 0 1 0 1 5 1 0 1 0 0 6 0 1 1 0 0 7 0 0 0 1 1 8 1 0 0 1 0 9 0 1 0 1 0 Table 1 uses a modified binary coded decimal encoding scheme. The four left-most bit positions for each character are assigned weights of 1, 2, 4 and 7, from left to right; the fifth position is used for an even parity bit. The su
29、m of the positional weights of the 1 bits is equivalent to the data character value, except in the case of the data character 0, where the weights 4 and 7 are applied. The parity bit ensures that there are always two 1 bits per character. The following algorithm defines the rules to convert numeric
30、data into the symbol characters of an Interleaved 2 of 5 symbol: Step in Algorithm Example 1) Calculate check character if required by the application standard. See 4.7; 2) If the data string, including check characters, has an odd number of digits, add a leading zero; which becomes 367 0367 3) Subd
31、ivide the numeric string into digit pairs; which becomes 0367 03 and 67 4) Encode each digit pair in turn as follows: a) Encode the leading digit of the pair into a pattern of bars as shown in Table 1; b) Encode the second digit of the pair into a pattern of spaces as shown in Table 1; 0 (binary pat
32、tern 00110) 3 (binary pattern 11000) 5) Form each symbol character pair by taking the bar and space elements alternately from the patterns derived from steps 4 a) and 4 b), commencing with the first bar of the pattern for the first digit, followed by the first space of the pattern for the second dig
33、it. Binary pattern 0101101000 Figure 1 illustrates the sequence of bar and space elements corresponding to the data character pairs “03 67“. BS ISO/IEC 16390:20074 06 NEXT CHAR. 37Figure 1 Interleaved 2 of 5 character pairs, encoding “03 67“ 4.3.3 Start and stop patterns The start pattern shall cons
34、ist of four narrow elements in the sequence bar - space - bar - space. The stop pattern shall consist of a wide bar - narrow space - narrow bar sequence. The start pattern shall be positioned at the normal left end of the data symbol characters adjacent to the first bar of the most significant digit
35、. The stop pattern shall be positioned at the normal right end of the data symbol characters adjacent to the final space of the least significant digit. There is no assigned human readable interpretation of the start and stop patterns and they shall not be transmitted by the decoder. Figure 2 illust
36、rates the start and stop patterns and their relationship to the symbol data characters. Quiet zone First char. Last char. Quiet zone START STOPFigure 2 Start and stop patterns BS ISO/IEC 16390:20075 Figure 3 illustrates a complete Interleaved 2 of 5 bar code symbol for the data “1234“ showing the ne
37、cessary quiet zones. Quiet zone Start 1st character pair 2nd character pair Stop Quiet zone 1234Figure 3 Interleaved 2 of 5 symbol inclusive of quiet zones 4.3.4 Optional symbol check character Annex A defines the check character position and calculation. 4.4 Dimensions Interleaved 2 of 5 symbols sh
38、all use the following nominal dimensions: width of narrow element (X): the X dimension of Interleaved 2 of 5 symbols should be defined by the application specification in accordance with the needs of the application in question. See 4.7.1; wide/narrow ratio (N): 2,0:1 to 3,0:1; minimum width of quie
39、t zone: 10X; recommended minimum bar code height for manual scanning: 5,0 mm or 15 % of symbol width excluding quiet zones, whichever is greater. The width, W (in millimetres) of an Interleaved 2 of 5 symbol, including quiet zones, can be calculated from the following expression: ( ) Q X N N P W 2 6
40、 6 4 + + + + = where: W is the symbol width; P is the number of symbol character pairs; N is the wide/narrow ratio; X is the width of a narrow element in millimetres; Q is the width of the quiet zone in millimetres. BS ISO/IEC 16390:20076 4.5 Reference decode algorithm Bar code reading systems are d
41、esigned 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. 1) Confirm presence of a leading quiet zone. 2) Confirm presence of a valid start patt
42、ern by checking that the widths of the initial four elements are each less than 7/64 the sum of the next ten elements (if this fails, reverse decoding may be attempted). 3) Decode the exact number of character pairs specified by the application as follows: (1) Record the widths of the ten elements o
43、f a character pair and accumulate their sum, S; (2) Compute a threshold, T = (7 / 64)S; (3) Compare the individual widths with the threshold: if element width is greater than T, assume element is wide; if not, assume it is narrow. 4) Verify that in each group of five bars and five spaces two bar and
44、 two space elements are wide and three bar and three space are narrow. 5) Using Table 1, convert the wide and narrow pattern of the five bars and five spaces respectively into the first and second digits of the digit pair. 6) After decoding the proper number of character pairs, confirm the presence
45、of a valid stop pattern by checking that the next element width is greater than or equal to the T of the previous symbol character and that the widths of the following two elements widths are less than T. 7) Confirm the presence of a trailing quiet zone. 4.6 Symbol quality 4.6.1 Test specification I
46、n order to verify whether a symbol meets the specifications in this International Standard it shall be tested using the test specification defined in ISO/IEC 15416, which defines a standardized methodology for measuring and grading bar code symbols, as supplemented in 4.6.2. ISO/IEC 15416 lays down
47、conditions under which measurements should be made; and defines methods of determining an overall quality grade based on the attributes of the bar code symbol. The reference decode algorithm defined in subclause 4.5 of this specification shall be used for the assessment of the “decode“ and “decodabi
48、lity“ parameters under ISO/IEC 15416. The overall symbol grade shall be expressed in the form shown in the following example: 1,5 / 10 / 660 where 1,5 is the overall symbol quality grade, 10 is the measuring aperture reference number (in this example 0,25 mm diameter), 660 is the peak response wavel
49、ength in nanometers. ISO/IEC 15416 allows for additional pass/fail criteria to be stipulated by a symbology specification. For Code 39, the additional criteria are given in 4.6.2. Any individual scan profile which does not meet these requirements shall receive a grade of 0. NOTE Certain application specifications may define a decode algorithm and a method of calculating the decodability value which differ from those specified in 4
