Code 11 is a

barcode A barcode or bar code is a method of representing data in a visual, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. These barcodes, now commonly referred to as linear or o ...

symbology developed by

Intermec Intermec is a manufacturer and supplier of automated identification and data capture equipment, including barcode scanners, barcode printers, mobile computers, RFID systems, voice recognition systems, and life cycle services. Intermec holds pate ...

in 1977. It is used primarily in telecommunications. The symbol can encode any length string consisting of the digits 0–9 and the dash character (-). A twelfth code represents the start/stop character, commonly printed as "*". One or two modulo-11 check digit(s) can be included. It is a discrete, binary symbology where each digit consists of three bars and two spaces; a single narrow space separates consecutive symbols. The width of a digit is not fixed; three digits (0, 9 and -) have one wide element, while the others have two wide elements. The valid codes have one wide bar, and may have one additional wide element (bar or space). The decode table has 15 entries because the symbols with two wide bars (1, 4 and 5) are listed twice. Assuming narrow elements are one unit wide and wide elements are two units, the average digit is 7.8 units. This is better than codes with a larger repertoire like

Codabar Codabar is a linear barcode symbology developed in 1972 by Pitney Bowes Corp. It and its variants are also known as Codeabar, Ames Code, NW-7, Monarch, Code 2 of 7, Rationalized Codabar, ANSI/AIM BC3-1995 or USD-4. Although ''Codabar'' has not b ...

(10 units) or

Code 39 Code 39 (also known as Alpha39, Code 3 of 9, Code 3/9, Type 39, USS Code 39, or USD-3) is a variable length, discrete barcode symbology. The Code 39 specification defines 43 characters, consisting of uppercase letters (A through Z), numeric digi ...

(11 units), but not quite as good as

interleaved 2 of 5 Interleaved 2 of 5 (ITF) is a continuous two-width barcode symbology encoding digits. It is used commercially on 135 film, for ITF-14 barcodes, and on cartons of some products, while the products inside are labeled with UPC or EAN. ITF encod ...

(7 units). The non-binary symbology

Code 128 Code 128 is a high-density linear barcode symbology defined in ISO/IEC 15417:2007. It is used for alphanumeric or numeric-only barcodes. It can encode all 128 characters of ASCII and, by use of an extension symbol (FNC4), the Latin-1 characters d ...

uses 5.5 units per digit (11 units per digit pair).

External links

Code 11 Symbology Specification
{{Barcodes Barcodes