BarCode Interleaved 2 of 5
Interleaved 2 of 5 encodes digits and is often used for product cartons. (The products themselves may have UPC or EAN barcodes.)
Each digit consists of 5 bars; each bar may be narrow or wide. Pairs of digits are coded together: the first digit of a pair uses black bars and the second digit uses white bars. Thus by interleaving a digit in black with a digit in white, two digits may be encoded concurrently.