I think the zero prefix only applies to values over 128.I guess it's the first variant with only one leading zero, right ?
Yes, the DOS ascii charset comes in different national variants called codepages, where the upper 128 chars varies. Examples: codepage 437 is the original US IBM charset with line drawing chars, codepage 865 is Danish/Norwegian with 3 altered chars, and codepage 850 is the international codepage where most of the line-drawing characters are replaced with accented characters and greek characters. If you goes to DOS from Windows you will usually be put in codepage 850.So is it right that both charsets now have 256 chars?
Ansi also comes in different codepages/charsets like Windows Western (1252), Windows Central European (1250) etc.