VMS Help DECnet-Plus, DCL Commands, SET, HOST, /X29, Qualifiers, /VMS_MODE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /NOVMS_MODE

    (Default=/NOVMS_MODE)

    This qualifier causes the PAD to enter VMS mode.

    This optimizes communication with the remote DTE if the system is
    VMS  V4.0  or  later.   Do  not use this qualifier unless you are
    connected to a VAX/VMS V4.0 or later system.