Epson 486SX User Manual page 109

Jumper settings for base memory
Base memory
640KB
512KB
256KB
Factory setting
l
Jumper settings for extended memory
Factory setting
l
Jumper settings for alternate 25 MHz microprocessor
Jumper
number
JP2
* Factory setting; these jumpers are not used for the 50 MHz microprocessor
6-6 Installing and Removing Options
Jumper JP13
A'
B
B
Jumper Function
setting
A 80487SX installed; NMI signal
B* 80486SX installed; NMI signal
80487SX installed; FERR signal
80486SX installed; FERR signal
Jumper JP14
A'
A
B