ASCII - American Standard Code for Information Interchange
Completely different from IBM's EBCDIC Extended Binary Coded Decimal Interchange Code encoding.
This 7-bit encoding is the defacto-standard encoding for Roman text and most ProgrammingLanguages. It was developed in the 60s and standardized in its current form in 1967.
Many 8-bit "high ASCII" encodings were derived from ASCII, mostly to represent letters with diacritical marks used in European languages. Latin-1 (ISO 8859-1) is the most common example seen on the web, as shown on AsciiValuesForUmlauts.
Modern encodings, such as UniCode, subsume ASCII. For BackwardsCompatibility, UtfEight represents the code points of ASCII using one byte.
JargonFile: http://www.catb.org/~esr/jargon/html/A/ASCII.html