Special characters are not transferred properly, why?
This may have various reasons: In case special characters from a latin characterset (e.g. "Ö") are replaced by strange characters (like "A|") on A-Class and older C- and E-Class handsets a base station update is recommended.
Please note that the handsets are preset in delivery state with an directory editor language. For the proper transfer of e.g. polish special characters, a handset with polish editor language is required. Same is valid for non-latin characters (e.g. Cyrillic, Greek). It's required to use also a handset with this special editor language set. Otherwise the cyrillic / greek characters will be converted to "?" If the handset is set to editor language e.g. cyrillic, some latin special characters cannot be transferred correctly (e.g. "Ö" -> "O"; "ß" -> "?")