Code 39 (also known as "USS Code 39", "Code 3/9", "Code 3 of 9", "USD-3", "Alpha39") is a bar code designation that can be used to encode large Latin letters (from A to Z), numbers (from 0 to 9) and some special characters (for example, the dollar sign '$').
Technical requirements for the Code 39 bar code symbology, character indexes, data character coding, dimensions, decoding algorithms, application parameters and prefix strings and symbol identifier in Russia are governed by GOST 30742-2001 (ISO / IEC 16388—99) “Automatic identification. Barcode coding. Specification of Code 39 Symbols (Code 39) ”.
Content
Code 39 Structure
The Code 39 barcode structure consists of six zones:
- White (free) field;
- Start symbol (Start);
- Coded information;
- The check character (checksum) is an optional parameter;
- Stop (Stop) symbol;
- White (free) field.
Character spacing (space) separates characters in a character.
Each character consists of 9 stripes, of which 3 are wide (one is white and 2 is black). The width of the wide strip can be from 2 to 3 narrow widths. Start and stop symbols are the same, are encoded in the same way as the symbols and are indicated by an “*” sign - an asterisk. [one]
The barcode of the Code 39 standard, unlike Code 128 , may not contain a check mark, which is allowed by the relevant standard.
In cases when it is necessary to increase the reliability of the encoded data, a control sign is used, which is located between the last data character and the “Stop” sign. The control sign is calculated as the sum of the values of all characters of the character modulo 43.
Since, according to the standard, there is a space between the characters, the width of which does not carry information, Code 39 can be specified with a font in a regular text editor. In this case, it is necessary to add an asterisk "*" at the beginning and at the end of the coded sequence.
Notes
- ↑ TradePilot . - Description of the standard barcode Code 39. Date of circulation November 29, 2009. Archived April 8, 2012.
Links
- Online barcode generator .
- Implementation in Python.
See also
- Code 128
- EAN-13