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

       /FALLBACK
       /NOFALLBACK

    Controls whether the 8-bit DEC Multinational character set
    characters are displayed on the terminal in their 7-bit
    representation. The default depends on the /EIGHTBIT setting of
    the terminal. If the OpenVMS Terminal Fallback Facility (TFF) is
    enabled, it activates the default character conversion tables for
    the named terminal. For more information, refer to the OpenVMS
    Terminal Fallback Utility Manual (available on the Documentation
    CD-ROM). If TFF is not enabled on your system, the /FALLBACK
    qualifier has no effect and no error message is displayed.