Interleaved 2 of 5
type of barcode
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 was created by David Allais, who also invented barcodes Code 39, Code 11, Code 93, and Code 49.
Encoding scheme
ITF encodes pairs of digits; the first digit is encoded in the five bars (or black lines), while the second digit is encoded in the five spaces (or white lines) interleaved with them. Two out of every five bars or spaces are wide, giving the name "2 of 5", and each pair has a consistent width. The wide lines form a two-out-of-five code with consecutive values of 1, 2, 4, 7, and 0, where the code 0 is assigned to the value of 11. This is similar to the POSTNET bar code.
The digits are encoded to symbols as follows:
where "n" is a narrow line (bar or space) and "W" a wide line (2.0 to 3.0 times the width of a narrow line).
Because digits are encoded by pairs, only an even number of digits can be encoded. Typically an odd number of digits is encoded by adding a "0" as first digit, but sometimes an odd number of digits is encoded by using five narrow spaces in the last digit.
A checksum can be added as last digit, which is calculated in the same way as UPC checksums.
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This entry incorporates text from “Interleaved 2 of 5” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.