Tektronix-4100 graphics terminal:
     Such as a Tektronix-4015, -4107, -4205, -4207 terminal.
     Full graphics functionality is supported on such a terminal.

ReGIS graphics terminal:
     Such as a GIGI, VT240, VT330, VT340 terminal.
     Following features are not supported on such a terminal:
     	o  Graphics input (GIN) or crosshair cursor.
     	o  Interactive layout utility.
     	o  Continuous font size and direction.
     	o  Screen saving or combination plot.

ANSI_protocol text terminal:
     Observe ANSI escape sequences for alpha-cursor control
     and character renditions such as a VT100 terminal. No
     screen graphics is supported on such a terminal but you
     can perform interactive dialogue and plot setup, and make
     a hardcopy. In general, most of terminals including the 
     graphics terminals listed above are VT100 compatible.
