128A (Code Set A) – Uses ASCII characters 00 to 95 (0–9, A–Z and control codes), special characters, and FNC 1–4
128B (Code Set B) – Uses ASCII characters 32 to 127 (0–9, A–Z, a–z), special characters, and FNC 1–4
128C (Code Set C) – Uses 00–99 (encodes two digits with a single code point) and FNC1
Defines which code set is used to create Code128. Please refer to the details about CodeSet