IBM RT Series Hardware Reference Manual page 221

Configuration Switch Settings
The configuration switches on the Enhanced Graphics Adapter
determine the type of display support the adapter provides, as
follows:
Switch Settings for Enhanced Graphics Adapter
as Primary Display Adapter
Configuration
Enhanced
Monochrome
Color/Graphics
SWI SW2 SW3 SW4 Adapter Adapter Adapter
On Off
Off On
Color Display Secondary
-
40x25
Off Off Off On Color Display Secondary
-
80x25
On On On Off Enhanced Display Secondary
-
Emulation Mode
Off On
On
Off Enhanced Display Secondary
-
Hi Res Mode
On Off On Off Monochrome
-
Secondary
40x25
Off Off On Off Monochrome
-
Secondary
80x25
IBM Enhanced Graphics Adapter 81