VMS Help SET, PRINTER, Qualifiers, /FALLBACK  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /FALLBACK
       /NOFALLBACK (default)

    Determines whether the printer attempts to translate characters
    belonging to the DEC Multinational character set into 7-bit
    equivalent representations. If a character cannot be translated,
    an underscore (_)  character is substituted.

    If the /PASSALL qualifier is in effect, it has precedence over
    the /FALLBACK qualifier.