Code Page Translation
Both the internal viewer and editor have a function to translate the code page of the file being viewed / edited. This is most useful when the file is in a code page that contains mostly the same glyphs as the current display code page. If a character in the file's code page doesn't exist in the display code page it will either be inaccurately translated or not translated at all.
The most common case is when you have a file written in an ANSI code page (EG 1252) and your display code page is 850 or 437. After pressing Alt-C and entering 1252, the file will become readable.
In OS/2 this function makes use of the Unicode API that was added to OS/2 for Open32. This means that it can only be used on Warp 4 or Warp 3 if FixPack 26 or later is installed.