Code 128 Bar Code Symbology

Code 128 is a linear (1D) type bar code that is a very compact bar code for all alphanumeric applications. The full (128-character) ASCII character set can be encoded in this symbology without the double characters found in extended Code 39. If the bar code has four or more consecutive numbers (0–9), the numbers are encoded in double-density mode (where two characters are encoded into one character position). Code 128 also has five special non-data, hidden control characters. Code 128 bar codes have a built-in check digit.