Linear Barcode Code 39 Introduction

Details of Code 39 symbology, application, and barcode features and Code 39 barcode generator for .NET applications
Generate, Create and Print Code 39 Images in .NET Applications provides comprehensive Code 39 barcode generator components for developers who needs to integrate Code 39 barcode into .NET applications using various generation methods.
Code 39 Barcode Symbology Overview
Definition of Code 39 Barcode
Code 39, which is also known as Alpha39, Code 3 of 9, Code 3/9, Type 39, USS Code 39, or USD-3, was developed by Dr. David Allais and Ray Stevens of Intermec in 1974. It is a discrete linear barcode, which is self-checking and bidirectionally decodable, with a variable length.
Application of Code 39 Barcode
  • United States Department of Defense standard barcode
  • Health Industry Bar Code Council (HIBCC) adopted barcode
  • Electronic Mechanism Industry Association of Japan (EIAJ) adopted barcode
Barcode Specification of Code 39 Barcode
  • ISO / IEC 16388 (2nd edition 2007-05-15)
  • HIBC (Health Industry Barcode)
  • LOGMARS (Logistics Applications of Automated Marking and Reading Symbols)
  • ANSI MH 10.8 M-1983 and ANSI/AIM BC1/1995, Uniform Symbology Specification
Linear Code 39 Barcode Features Overview
  • Encodable character set of Code 39 includes full alphanumeric A to Z and 0 to 9, special characters like space $ % + - . / (complying with ISO 646) and stop/start character *.
  • It has 9 elements per symbol character, of which 3 are wide and 6 are narrow, comprising 5 bars and 4 spaces; it is 13 to 16 modules per symbol character, inclusive of minimum intercharacter gap and its density depends on wide bar to narrow bar ratio.
  • It’s self-checking when a single erroneously interpreted bar cannot generate another valid character, and it has one optional symbol check character.
  • Code 39 non-data overhead is equal to 2 symbol characters (start/stop character).
Code 39 Barcode Structure Overview
A Code 39 includes, from left to right, leading quiet zone, start character, one or more symbol characters representing data (including symbol check character, if present.), stop character and trailing quiet zone.
Linear Code 39 Barcode Dimension Overview
Barcode Width of Code 39
The dimensions of Code 39 should obey the following rules: a) Width of narrow element, noted by X, is defined by the application specifications. b) The wide/narrow ratio (N) is ranging from 2.0/1 to 3.0/1. c) the minimum width of intercharacter gap amounts to X while the maximum is 5.3X (X < 0.287mm) and 1.52mm or 3X (X≥ 0.287mm. d) The minimum width of quiet zone amounts to 10X.
Barcode Height of Code 39
5.0mm or 15% of symbol width (quiet zone excluded) is the recommended minimum bar code height for manual scanning.
Code 39 Check Digit Calculation Example
For some special applications, like LOGMARS (Logistics Applications of Automated Marking and Reading Symbols), HIBC (Health Industry Barcode), a Code 39 checksum digit is needed to improve its data accuracy. Below is the way of how to calculate Code 39 MOD43 check character.
  • Take each data character’s value.
  • Add up all the values.
  • Divide the result by 43 and get the remainder.
  • The remainder is the value of the check character.
For example, following are steps of calculating the check character of the data characters "TERREK":
  • The values are 29, 14, 27, 27, 14 and 20.
  • When added together, these total 131.
  • Now divide 131 by 43 and the remainder is 2.
  • The check character is 2