I'm under the impression that mIRC 7.x only supports a single charset (unicode). Is this not accurate?
it's the $utf*code identifiers that support other charsets :P
$utfdecode(txt , C) can be used to convert text to Unicode as though it were a series of bytes in charset C. one or more of these charsets contain unreadable characters where the latin alphabet should be. just as $decode(unreadable text, m) can be used to hide readable text/code, so too can $utfdecode(unreadable, C) for certain Cs.