Code 128

Code 128 is a high-density, linear (1D) barcode symbology widely used for alphanumeric or numeric-only barcodes. It can encode all 128 ASCII characters, and, by using function codes, can switch character sets within a single barcode.

Description:

Code 128 is a variable-length barcode, meaning that the length of the barcode is determined by the data it encodes. It's considered a relatively complex symbology compared to others like Code 39, but its high density allows for a shorter barcode representation of the same data. This makes it particularly suitable for applications where space is limited. The barcode consists of start characters, data characters, check character, and a stop character.

Key Features:

• High Density: Encodes more data in a smaller space compared to many other 1D barcode types.
• Full ASCII Character Set: Supports all 128 ASCII characters, including uppercase and lowercase letters, numbers, punctuation, and control characters.
• Three Character Sets (A, B, C): Allows for optimized encoding of different types of data. Character set A is optimized for uppercase letters and control characters. Character set B is optimized for uppercase and lowercase letters, as well as numbers and punctuation. Character set C is optimized for encoding numeric data in pairs, allowing for higher density when encoding purely numeric data.
• Function Codes: Function codes within the data stream enable switching between character sets for optimal encoding efficiency.
• Check Character: Includes a modulo 103 check character for error detection. This helps to ensure the accuracy of scanned data.
• Start and Stop Characters: Specific start and stop characters indicate the beginning and end of the barcode. The start character determines the initial character set to be used.

Applications:

Code 128 is utilized in a variety of industries and applications, including:

• Shipping and Logistics: Used for tracking packages, labeling shipments, and managing inventory.
• Healthcare: Used for identifying medications, labeling medical records, and tracking patient specimens.
• Manufacturing: Used for tracking components, managing work-in-process inventory, and labeling finished goods.
• Retail: Used for product labeling, inventory management, and point-of-sale systems.
• Library Management: Used for identifying books and other library materials.

Variations:

Several variations of Code 128 exist, including:

• GS1-128 (formerly EAN-128): A variation of Code 128 used for encoding GS1 application identifiers, which provide information about the type of data encoded in the barcode (e.g., expiration date, batch number).
• SSCC-18: A specific application of GS1-128 used to encode the Serial Shipping Container Code (SSCC), a unique identifier for logistics units.