Code39

The coding Code39, also called short 3of9, represents an alphanumeric character set available. In addition to seven digits and uppercase characters are defined. Start and stop characters are the same and "*" are represented by the symbols. The Code39 is specified in ISO / IEC 16388.

Construction

Code 39 is the name of the structure of the code, with three wide elements out of a total number of nine back. This structure allows the display of 44 different characters. Therefore, the last 5 characters ( value for checksum 38-42) are presented in another form ( 3 wide white bars instead of 2 black and 1 white wide beam ). 38 of 40 ways to meet the numbers 0-9, the alphabet ( AZ), the point and the comma. The 39 include the possibility Start-/Stoppzeichen, * '. The 40th option ( sWSwswSws - s = thin black, S = thick black; w = skinny white; W = thick white) is not used. Each character of the alphabet is assigned a barcode of five bars and four spaces. There are two different bar and space widths.

Code39 is a discrete code with variable length code (variable number of characters). The code structure permits bidirectional scanning of the self-checking elements.

For applications with high demands on the reading security exists an optional checksum which is based on a table of values ​​for each character. This has the character '0 ', the numeric value 0, the character '1' is 1, the character 'A' is 10, the character Z 'has the value 35 as the last character is '%', the value 42 is associated. The value of the check character is calculated accordingly as follows:

For example, is the mark of the string, 12345abcde / ' the ' T '. By following calculation is the 'T' concluded:

The Code39 is easy to manufacture as a sign plain text corresponding to a character barcode. Code39 dominated earlier application areas that demanded an alphanumeric coding. Because of the relatively low information density and a low in comparison to other encodings character set selection, but is increasingly being replaced in recent times by the Code128.

Encoding

Full ASCII Code 39

Code 39 is limited to 43 characters. In order to display all 128 ASCII characters, the system will be expanded: The symbols 0-9, AZ,, ' and' - ' are the same as Code 39 lowercase letters, other characters and control characters are replaced by two consecutive symbols. formed by Code39.

Symbol Table Full ASCII Code 39

Code 39 Reduced

Is a variant that consists of only the characters 0 through 9 and A through Z and the check character is calculated modulo 36.

Support

As a long-standing symbolism code is supported by 39 almost all popular bar code readers and label printers. For word processing software code is the font from different vendors (also free) offered 39, and LaTeX is recommended that barcodes package.