VMS Help CMS, Qualifiers, /INTERFACE[=interface]  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Invokes CMS in either the character cell (terminal) or
    DECwindows environment.  You must have CMS installed on your
    system.  You can specify one of the following interfaces:

    o  CHARACTER_CELL
    o  DECWINDOWS

    Specify the  CHARACTER_CELL keyword to invoke CMS as a sub-
    system in the command-line interface.  Whether you type the
    CMS  command,  the  CMS/INTERFACE  command,  or  the
    CMS/INTERFACE=CHARACTER_CELL command, the default is to invoke
    the CMS command-line interface.

    Specify the DECWINDOWS keyword to invoke the CMS DECwindows
    interface  (CMS Version 3.2 or higher).   You must have
    DECwindows installed on your system.  The DECwindows interface
    is a graphical interface to CMS, and runs on a terminal or
    terminal emulator on a DECwindows workstation.