2The of5 barcode was developed 40 years ago. This is a low density variable length number. This barcode is used in the manufacturing industry and is called Code 25, Code 25 Standard and Code 25 Industrial. Rarely used these days..

"2 of 5 Standard" barcode. "1234567890" is the number encoded in the barcode.

The 2of5 Interleaved barcode is a high density variable length barcode evolved from the 2of5 Standard barcode. Used in many fields to encode digital data, it is an international standard code for marking and packaging shipping units.

Characters are coded in pairs. The first character of the pair is encoded with the width of the stroke, the second character of the pair is encoded with the width of the space separating these strokes. The barcode is therefore called interleaved and is denser than the 2of5 standard. Odd numbers of characters are automatically prepended with “0”.

"2of5 interleaved" barcode. "1234567890" is the number encoded in the barcode.