ASCII
From AMule Project FAQ
ASCII is a character set and codification which includes most the common English characters and symbols. It is reduced to 127 characters, which happens to be far below the amount of characters needed to suit the needs of all users around the worls. Therefore, the Unicode standard appeared.
Some extensions allow ASCII to set up to 256 characters but this bring incompatibilities between users using different extensions.
More information can be found at Wikipedia's ASCII article.
