/FILTER_CTRL
       /NOFILTER_CTRL (default)

    For interactive PMDF MAIL sessions, specifying /FILTER_CTRL turns
    on the filtering out of 7-bit and 8-bit control characters in
    messages. Messages which contain such control characters can
    cause problems with the terminal when they are displayed. When
    /FILTER_CTRL is specified, such a character is displayed as its
    hexidecimal value in the format "=XX".