A mapping from a set of integers to a set of characters. This mapping is generally 1:1 (i.e., bijective), for example, the code position 65 in ASCII maps only to "A", and it's the only position that maps to "A".

There are several standard coded character sets, the most widely used is ASCII, generally in its Latin-1 dialect, with Unicode becoming slowly more common; while EBCDIC and Baudot are extinct except in legacy systems.

A coded character set may include letters, digits, punctuation, control codes, various mathematical and typographic symbols, and other characters. Each character in the set is represented by a unique character code (or "code position").