Epson Progression U12 - Manual (Page 89)

486DX/33
W1,W2.W3
There is only one jumper on
the 486SX/25 card,
and it should
always be set to position B.
If you have the 486DX/33 card, refer to the following table to
make sure the jumpers are set correctly before you install the
card in your computer, and change them if necessary.
486SX/33 CPU card jumpers
Jumper setting
CPU card configuration
W1 W2 W3
Card only; no OverDrive module A A A
ODP486DX/33 module installed
For general information on setting jumpers, see “Jumper
Settings” on page 3-4.
3-20 Installing and Removing Options