- Code 128 is a very effective, high-density symbology which permits the encoding of alphanumeric data.
- It can encode all 128 characters of ASCII and, by use of an extension character (FNC4).
- The symbology includes a checksum digit for verification and the bar code may also be verified character-by-character verifying the parity of each data byte.
- This symbology has been widely implemented in many applications where a relatively large amount of data must be encoded in a relatively small amount of space.
Structure of Code 128
- A Code 128 bar code consists of a leading quiet zone, one of three start codes, the data itself, a check character, a stop character, and a trailing quiet zone.
- Code 128 does not have 128 distinct symbols, so it cannot represent 128 code-points directly.
- To represent all 128 ASCII values, it shifts among three code sets (A, B, C).
- Code Set A represents ASCII characters 00 to 95 (0–9, A–Z and control codes), special characters and FNC 1–4.
- Code Set B represents ASCII characters 32 to 127 (0–9, A–Z, a–z), special characters, and FNC 1–4.
- Code Set C represents 00–99 (encodes two digits with a single code point) and FNC1.
Advantages
- It store large amount of data in small barcode.
- Can encode all the ASCII characters (including all special characters) unlike code 39 which could encode only six special characters.
- Provides more security over encoded data and minimized chances of error while scanning.
Disadvantages
- It is not easy to print barcode with four different width variations per element.
- More advanced scanning devices are required to scan these bar codes.
- Like other linear barcodes, code 128 is also subjected to distortions and can be damaged easily.
Applications
- Commonly used in shipping industry to identify containers and items.
- Used in packaging and whole sale industry to identify and label variety of whole sale items.
- Widely used in combination with code 39 in all the advanced brick and mortar companies.
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