Library /sys$common/syshlp/sysmanhelp.hlb DEFINE, /KEY, Qualifiers, /ECHO  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /ECHO (default)
       /NOECHO

    Specifies whether the command line echoes after you press the
    defined key. Note that you cannot define a key using both the
    /NOECHO and /NOTERMINATE qualifiers.