Code I 2 of 5
Interleaved 2 of 5 (also called I-2/5 and ITF) is suitable for encoding general purpose all-numeric data. Reference symbology for UCC/EAN Shipping Container Symbol. Character encodation, reference decode algorithm and optional check character calculation are included in this document. This specification is intended to be significantly identical to corresponding Commission for European Normalization (CEN) specification.
Interleaved 2 of 5 is a a numbers-only bar code. The symbol can be as long as necessary to store the encoded data. The code is a high density code that can hold up to 18 digits per inch when printed using a 7.5 mil X dimension. A check digit is optional.
The "Interleaved" part of the name comes from the fact that a digit is encoded in the bars and the next digit is encoded in the spaces. The encoded digits are "Interleaved" together. There are five bars, two of which are wide and five spaces, two of which are wide.
The symbol includes a quiet zone, the start character (narrow bar-narrow space- narrow bar-narrow space), the encoded data, the stop character (Wide bar-narrow space-narrow bar), and a trailing quiet zone.
The Distribution Symbology Study Group has recommended 2 of 5 as the standard for numeric labeling of corrugated shipping containers. It has been adopted by the Uniform Product Code Council as the standard symbology for outer shipping containers in the grocery industry. It is also used in the medical and automotive fields.
Bearer bars are used to help prevent the partial scan from being decoded as a valid Interleaved 2 of 5 symbol. They must touch the top and bottom of all of the data bars. Minimum width of bearer bars should be three times of the narrow bar width. This will eliminate the possibility of a partial scan that could still be decoded.
Code I 2 of 5 Characteristics
Character Set: 0 - 9
Encodation: I2 of 5 pairs characters and encodes the first digit of the pair on five bars and the second digit of the pair on the five interleaving spaces. Two of the five spaces or bars used to encode a character are always wide.
Start/Stop Pattern: Starts with four narrow elements beginning with a bar, and stops with a wide bar followed by two narrow elements.
Code Type: Binary, varying length. I2 of 5 requires an even number of digits to encode information.
Human Readable: Optional, although it is typically used.
Check Digit: Optional; however, Modulus 10 required when using the SCC-14 specification.
Encoded Information: Contingent upon data requirements although an even number of digits is required. A leading zero is used if there is an odd number of digits available.
Minimum "X" Dimension: 0.075 inches
Wide to Narrow Ratio:
2:1 to 3:1 with "X" Dimension > .020 inches
2.2:1 to 3:1 with "X" Dimension < .020 inches
The SSC-14 specifications outline "magnifications" that are allowable.
Allowable Symbol Height: The greater of .25 inches or 15% of the symbol length. | 
