Question 1

What is a Code 128 barcode?

Accepted Answer

Code 128 is a high-density linear barcode that can encode all 128 ASCII characters (0-127). It is widely used in shipping, packaging, logistics and the GS1-128 standard. It has three code sets: A (uppercase, control), B (upper/lowercase, punctuation) and C (compact double-digit pairs).

Question 2

How is the Code 128 check digit calculated?

Accepted Answer

Code 128 uses a modulo-103 check digit. Starting with the start code value (103, 104 or 105), each subsequent character's value is multiplied by its position (starting at 1) and summed. The total mod 103 gives the check character, which the tool calculates automatically.

Question 3

What is the difference between Code 128 A, B and C?

Accepted Answer

Code Set A encodes uppercase letters, digits, symbols and control characters. Code Set B encodes uppercase, lowercase, digits and symbols. Code Set C encodes pairs of digits in a single symbol, making numeric data about twice as compact. Auto mode switches between sets to produce the shortest barcode.

Question 4

Are the generated Code 128 barcodes scannable?

Accepted Answer

Yes. Barcodes are generated strictly to the ISO/IEC 15417 Code 128 specification with correct bar widths, quiet zones, check digit and human-readable text. Any standard barcode scanner can read them.