Code39

Code39 is an alphanumeric barcode which allows for the representation of numerals 0 through 9, all 26 letters (without vowel mutations) and a total of seven special characters. Each character is made up of nine elements (five bars and four spaces (space)) of which three are wide and six are narrow, except in the case of the special characters. The spaces between the bars do not contain any information. Code39 has a tight tolerance and a relatively small information density.