IBM RT PC Options Installation page 200

7-8 Options Installation
Use this table to set the switches if any of the following conditions
are present:
• The IBM Personal Computer Display (5151) is attached to the
Enhanced Graphics Adapter.
• The IBM Personal Computer Display (5151) is assigned to the AT
Coprocessor Adapter in dedicated mode.
• Another display is also installed and assigned to the AT
Coprocessor Adapter in dedicated mode.
IBM 5151 Display
Assignment
Primary
Primary
Secondary
Secondary
Second Display
Mode of
Operation Sw1
80 X 25 Color Off
40 X 25 Color On
80 X 25 Color Off
40 X 25 Color On
Sw2 Sw3 Sw4
Off On Off
Off On Off
On Off On
On Off On