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.