Extended ASCII
Definition of Extended ASCII
"Extended ASCII" is an informal umbrella term for any 8-bit encoding that adds 128 characters (positions 128-255) on top of the original 7-bit ASCII. There is no single "Extended ASCII" standard - the term covers dozens of incompatible encodings including ISO-8859-1, CP437, Windows-1252, and many others.
This ambiguity causes real problems. Code 0x80 is a Euro sign in CP1252, a Latin capital C-cedilla in ISO-8859-1, and a C-cedilla again but with different surrounding characters in CP437. When someone says "extended ASCII," always ask which encoding they mean. Compare encodings on our comparison page to see exactly where they differ. For new projects, skip extended ASCII entirely and use UTF-8.
This ambiguity causes real problems. Code 0x80 is a Euro sign in CP1252, a Latin capital C-cedilla in ISO-8859-1, and a C-cedilla again but with different surrounding characters in CP437. When someone says "extended ASCII," always ask which encoding they mean. Compare encodings on our comparison page to see exactly where they differ. For new projects, skip extended ASCII entirely and use UTF-8.