TTYPortEnvironment.mesa
Copyright (C) 1980, 1985, 1986 by Xerox Corporation. All rights reserved.
Tim Diebert: November 16, 1985 6:28:36 pm PST
Bill Jackson (bj) July 31, 1986 0:17:57 am PDT
Defines basic, hopefully unchanging TYPEs
required by BOTH the TTY Port channel (TTYPort)
and device face (TTYPortFace),
thus preventing interdependencies.