Datatech Enterprises Apex 386SX/20 User Manual page 110

Indicate two parameters for EMS-page register I/O base address and
frame start address.
You will get a warning if you give an incorrect response. For example,
if you give D000H as your frame start segment, and shadow RAM in
the same area, the following message will appear.
12 Chapter 6: Appendix
• A screen like the following will appear.
• Choose the correct configuration as you desire, then press
<F1> to complete setup.