American Standard Code for Information Interchange:
Worldwide use.
Figures, letters, special and device control characters are presented as 7-bits-binary combinations.
The standard-ASCII-character set comprises 27 = 128 sets.
An eighth bit serves as a so-called parity bit for error detection when ASCII-files are transmitted. When the parity control results in an even figure, this bit will be set to '0', provided that the number of 'ones' of the remaining bits is even. Otherwise it is set to '1'. The extended ASCII character set makes no parity control. Here the bit of the highest value is used for the purpose to switch from the standard character set to the extension. This allows space for country-specific special characters.
Link:
ASAM
