Aaeon PCM-7890 User Manual page 35

You can use J4 to clear the CMOS data if necessary. To reset the
CMOS data, set J4 to 2-3 closed for just a few seconds, and then
move the jumper back to 1-2 closed.
J4
*default
The 9th pin of COM3 and COM4 (9-pin D-sub connector) can be
selected as RI, +5V, or +12V by setting J5 & J6.
J5
J6
*default
Protect*
1
2
3
RI*
1 3 5
2 4 6
RI *
1 3 5
2 4 6
+5V
1 3 5
2 4 6
+5V
1 3 5
2 4 6
Chapter 2 Installation 23
Clear CMOS
1
2
3
+12V
1 3 5
2 4 6
+12V
1 3 5
2 4 6