Asus P1-AH2 - Manual (Page 53)

4-4 Chapter 4: Motherboard info
2. USB device wake-up (3-pin USBPW12, USBPW34,
USBPW56)
Set these jumpers to +5V to wake up the computer from S1 sleep
mode (CPU stopped, DRAM refreshed, system running in low power
mode) using the connected USB devices. Set to +5VSB to wake up
from S3 and S4 sleep modes (no power to CPU, DRAM in slow refresh,
power supply in reduced power mode).
• The USB device wake-up feature requires a power supply that can
provide 500mA on the +5VSB lead for each USB port; otherwise,
the system would not power up.
• The total current consumed must NOT exceed the power supply
capability (+5VSB) whether under normal condition or in sleep mode.
R
USB device Wake up
(Default) +5V +5VSB
2 3 1 2
USBPW56
USBPW12
1
2
+5V(Default) +5VSB
3
2
(Default) +5V +5VSB
2 3 1 2
USBPW34