Code 128

Application

Code 128 is used in many areas because it has a very high information density and can encode numerous characters. Its main area of application is in the logistics sector. Printed on barcode labels, it ensures efficient processes because it can be used to uniquely and automatically identify all transport and storage units using a barcode scanner.

Three character sets

There are three character sets for Code 128, which encode different characters.

• Code128A à contains uppercase letters and special characters.
• Code128B à includes uppercase and lowercase letters.
• Code128C à This code is specially optimised for displaying numbers. Numbers can be given in pairs (00 to 99).

Structure of Code 128

The code is made up of the following units:

1. Quiet zone (white area before or after the barcode that clearly separates the code from other information)
2. Start character (indicates to the scanner the start of the barcode and from which character set – A, B or C – to expect for decoding)
3. Information
4. Check digit (ensures the correctness of the barcode. This part is only used for checking during the reading process. Since the check digit is not part of the value, it is not displayed as a readable character below the barcode).
5. Stop character (indicates the end of the barcode)
6. Quiet zone (white area before or after the barcode that clearly separates the code from other information)

The symbology of Code 128 is based on four different bar and space widths.

Difference to the GS1-128 code

The GS1-128 barcode (formerly EAN 128) is based on Code 128. However, it can also encode different information in one code.