Code 128 is a barcode developed in 1981. It is a variable length, high density, alphanumeric symbology. It can display 128 ASCII characters and is valid for numbers as well. Information can be encoded in three pairs of symbols, each with four types of barcodes. There are four types: Code128a, Code128b, Code128c, and Code128auto. (Automatically switch between Code128a, Code128b and Code128c barcodes to encode ASCII values). A distinctive feature of the 'c' charset is the ability to encode 100 pairs of numbers. This allows for double the recording density when encoding digital data.

A barcode element consists of 3 bars and 3 spaces. Bars and spaces are modular, with widths from 1 to 4 modules. The width of the element consists of 11 modules. The “Stop” sign consists of 13 modules, 4 bars and 3 spaces. The checksum is calculated automatically and is not visible in the barcode signature.

"Code128c" barcode. "0123456789012345" is the number encoded in the barcode.