2
In [xoops root dir]/language/[language name]/global.php
//%%%%% LANGUAGE SPECIFIC SETTINGS %%%%%
define('_CHARSET', 'ISO-8859-1');
define('_LANGCODE', 'en');
// change 0 to 1 if this language is a multi-bytes language
define("XOOPS_USE_MULTIBYTES", "0");
I think charset is what you are looking for.
Rowd