Code 11 is a numeric symbology and its character set consists of 10 digital characters and the dash symbol (-). 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -.
Code 11 is not secure in that printing imperfections can quite easily convert one character into another valid character. Data integrity is obtained by using one, or sometimes two, check characters. Code 11 is an older discrete, non-self-checking numeric symbology that was used by a number of large organizations, but is rarely found on retail scanners.
Code 11 barcodes can contain only digits and the - symbol. It can be used with one or two Mod 11 check characters, with the - symbol used when the check character value is 10. Code 11, also known as USD-8, is designed for telecom industry. Code11 barcode encodes numeric data and hyphen. Start and stop characters are mapped to asterisk. At least one check digit is required. When string length is longer than 10, two check digits are required. This is to prevent decoding error caused by printing device inaccuracies.
Structure of a Code 11 barcode
Code 11 barcode has the following structure: