Asus M2N-MX - Manual (Page 29)

ASUS M2N-MX 1-19
2. USB device wake-up (3-pin PS2_USB_PWR)
This jumper allows you to enable or disable the keyboard wake-up
feature. Set this jumper to pins 2-3 (+5VSB) to wake up the computer
when you press a key on the keyboard (the default is the Space Bar).
This feature requires an ATX power supply that can supply at least
500 mA on the +5VSB lead, and a corresponding setting in the BIOS.
M2N-MX
R
M2N-MX USB Device Wake Up
3 2 2 1
PS2_USB_PWR
(Default)
+5V +5VSB