A code that assigns the numbers 0 through 127 to the letters of the alphabet, the digits 0 through 9, punctuation marks, and certain other characters. For example, the capital letter A is coded as 65 (binary 1000001). By standardizing the values used to represent written text, ASCII enables computers to exchange information. Basic, or standard, ASCII uses seven bits for each character code, giving it 27, or 128, unique symbols. Various larger character sets, called extended ASCII, use eight bits for each character, yielding 128 additional codes numbered 128 to 255. Compare Unicode.