BS-EN-799-1996.pdf

BRITISH STANDARD BS EN 799:1996 Bar coding Symbology specifications “Code 128” The European Standard EN 799:1995 has the status of a British Standard ICS 35.040 Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 07 03:50:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 799:1996 This British Standard, having been prepared under the direction of the Information Systems Technology Assembly, was published under the authority of the Standards Board and comes into effect on 15 May 1996 © BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference IST/34 Draft for comment 92/66843 DC ISBN 0 580 25390 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee IST/34, Bar coding, upon which the following bodies were represented: Article Number Association (UK) Ltd. Association of British Health-care Industries Association of the British Pharmaceutical Industry Auto ID User Association Automatic Identification Manufacturers Association (Aim UK) Brewers Society British Iron and Steel Producers Association British Office Systems and Stationery Federation CCTA (the Government Centre for Information Systems) Engineering Employers Federation Flexible Packaging Association Food and Drink Federation Kings Town Photocodes Ltd. Kodak Limited Ministry of Defence National Association of Paper Merchants Process and Packaging Machinery Association Society of Motor Manufactures and Traders Limited Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 07 03:50:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 799:1996 © BSI 09-1999i Contents Page Committees responsibleInside front cover National forewordii Foreword2 Text of EN 7993 Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 07 03:50:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 799:1996 ii © BSI 09-1999 National foreword This British Standard has been prepared by Technical Committee IST/34 and is the English language version of EN 799:1995, Bar coding Symbology specifications “Code 128”, published by the European Committee for Standardization (CEN). This British Standard is published under the direction of the Information Systems Technology Assembly whose Technical Committee IST/34 has the responsibility to: aid enquirers to understand the text; present to the responsible European committee any enquiries on interpretation, or proposals for change, and keep UK interest informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, BSI, 389 Chiswick High Road, London, W4 4AL. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 16 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 07 03:50:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN 799 August 1995 ICS 35.040 Descriptors: Data processing, character recognition, optical recognition, graphic characters, alphanumeric character sets, bar codes, symbols, characteristics English version Bar coding Symbology specifications “Code 128” Code à barres Spécifications des symbologies “Code 128” Strichcodierung Symbologiespezifikationen “Code 128” This European Standard was approved by CEN on 1995-06-22. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels © 1995 All rights of reproduction and communication in any form and by any means reserved in all countries to CEN and its members. Ref. No. EN 799:1995 E Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 07 03:50:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 799:1995 © BSI 09-1999 2 Foreword This European Standard has been prepared by the Technical Committee CEN/TC 225, Bar coding, of which the secretariat is held by NNI. Organizations contributing to the development of the standard include: AIM Europe (Automatic Identification Manufacturers). NOTENot all of the symbologies which appear in this document are defined in European Standards; for information on current European Standards contact the CEN Central Secretariat or national standards organizations. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 1996, and conflicting national standards shall be withdrawn at the latest by February 1996. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword2 Introduction3 1Scope3 2Normative references3 3Definitions3 4Requirements3 Annex A (normative) Additional features of “Code 128”13 Annex B (normative) Special considerations relating to function code 1 (FNC1)13 Annex C (informative) Guidelines for the use of “Code 128”14 Annex D (informative) Symbology identifier14 Annex E (informative) Use of start, code set and shift characters to minimize symbol width14 Annex F (informative) Examples of application-defined parameters15 Annex G (informative) Relationship of symbol character value to ASCII value16 Figure 1 “Code 128” symbol encoding “CEN”5 Figure 2 “Code 128” start and stop characters5 Figure 3 Example of symbol character C5 Figure 4 Tolerance measurements8 Figure 5 Tolerance values for “Code 128” symbols9 Figure 6 Decode measurements9 Table 1 “Code 128” character encodation7 Table 2 Edge differences for decoding code 12811 Table D.1 Values of m for “Code 128”14 Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 07 03:50:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 799:1995 © BSI 09-19993 Introduction The technology of bar coding is based on the recognition of patterns encoded in bars and spaces of defined dimensions. There is a number of methods of encoding information in bar code form, known as symbologies, and the rules defining the translation of characters into bar and space patterns and other essential features are known as the symbology specification. “Code 128” is one such symbology. Previously symbology specifications have been developed and published by a number of organizations resulting in certain instances in conflicting specifications 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. 1 Scope This standard specifies the requirements for the bar code symbology known as “Code 128”; specifies “Code 128” symbology characteristics, data character encodation, dimensions, tolerances, decoding algorithms and application-defined parameters; defines a subset of “Code 128” assigned to EAN International. 2 Normative references This European Standard incorporates by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed below. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. prEN 1556, Bar coding Terminology. prEN 1635, Bar coding Test specifications for bar code symbols. ISO 646:1991, Information technology ISO 7-bit coded character set for information interchange. ISO 8859-1:1987, Information processing 8-bit single-byte coded graphic character sets Part 1: Latin alphabet No. 1. 3 Definitions For the purposes of this European Standard the definitions in prEN 1556 apply. 4 Requirements 4.1 Symbology characteristics The characteristics of “Code 128” are: a) encodable character set: 1) All 128 ASCII characters, i.e. ASCII characters 0 127 inclusive, in accordance with ISO 646. (Code subset C see 4.3.3.3 permits two numeric data digits to be expressed in one symbol character.) Characters with ASCII values 128 255 in accordance with ISO 8859-1 may also be encoded. See 4.3.4.3 d); 2) 4 non-data function characters; 3) 4 code subset selection characters; 4) 3 start characters; 5) 1 stop character; b) code type: continuous; c) elements per symbol character: 6, comprising 3 bars and 3 spaces, 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) data string length encodable: symbol length: variable; f) bidirectionally decodable: yes; g) symbol check character: one, mandatory (see A.1); h) Symbol character density: 11 modules per character (equivalent to 5.5 modules per data character in code subset C) (13 modules for stop character); i) non-data overhead: equivalent to 35 modules. 4.2 Symbol structure “Code 128” symbols shall comprise: a) leading quiet zone; b) start character; c) one or more characters representing data and special characters; d) symbol check character; e) stop character; f) trailing quiet zone. Figure 1 illustrates a “Code 128” symbol. 4.3 Character encodation 4.3.1 Symbol character encodation Table 1 defines all the “Code 128” character assignments. In the column headed “Symbol Character Structure” the numeric values represent the widths of the elements in modules or multiples of the X dimension. Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 07 03:50:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 799:1995 4 © BSI 09-1999 The sum of the bar modules in any symbol character shall always be even (even parity) and that of the space modules is therefore always odd. This even parity feature enables character self-checking to be carried out. Figure 2 below illustrates start character A and the stop character. Figure 3 below illustrates the encodation of the character C. 4.3.2 Data character encodation “Code 128” has three unique data character subsets shown in Table 1 as code A, B, and C. The symbol character bar and space patterns shown are equivalent to the data characters listed under the columns for code A, B, or C. The choice of data character subset depends on the Start character or the use of code set A, code set B or code set C characters or the Shift character. If the symbol begins with start character A, then code A subset is defined. Code B or code C subsets are similarly defined by beginning the symbol with start character B or C. The code subset can be redefined within the symbol by code set characters A, B or C, or the shift character. (See 4.3.4.2 for the use of these special characters.) NOTEEvery symbol character ends in a space which varies from one to four modules in width (except for the stop character, which ends in a two-module bar). The numeric values in the B and S columns represent the number of modules in each bar or space element respectively in the symbol characters. 4.3.3 Code subsets 4.3.3.1 Code subset A Code subset A includes all of the standard upper case alphanumeric keyboard characters and punctuation characters together with the control characters, i.e. characters with ASCII values from 00 to 95, and seven special characters. 4.3.3.2 Code subset B Code subset B includes all of the standard upper case alphanumeric keyboard characters together with the lower case alphabetic characters (i.e. ASCII characters 32 to 127 inclusive) and seven special characters. 4.3.3.3 Code subset C Code subset C includes the set of 100 digit pairs from 00 to 99 inclusive, as well as three special characters. This allows numeric data to be encoded, two data digits per symbol character, at effectively twice the density of standard data. 4.3.4 Special characters The last seven characters of code subsets A and B (character values 96 102) and the last three characters of code subset C (character values 100 102) are special non-data characters with no ASCII character equivalents, which have particular significance to the bar code reading device. 4.3.4.1 Start and stop characters Start characters A, B and C shall define the corresponding code subset to be used initially in the symbol. The stop character shall be common to all subsets. Start and stop characters shall not be transmitted by the decoder. 4.3.4.2 Code set and shift characters Code set and shift characters shall be used to change from one code subset to another within a symbol. They shall not be transmitted by the decoder. a) Code set characters: Code set A, B or C characters change the symbol code subset from the subset defined previously to the new code subset defined by the code character. This change applies to all characters following the code set character until either the end of the symbol or another code set character is encountered. b) Shift character: The shift character changes the code subset from A to B or B to A for the single character following the shift character. Characters following the affected character shall revert to the code subset A or B defined prior to the shift character. 4.3.4.3 Function characters Function characters (FNC) define instructions to the bar code reading device to allow for special operations and applications. a) FNC1 shall be subject to the special considerations defined in Annex B. b) FNC2 (mess