Asus P3-P5G31 - Manual (Page 56)

4-4 Chapter 4: Motherboard info
2. USB device wake-up (3-pin PS2_USBPW)
This jumper allows you to wake up the computer from S1 mode (CPU
stopped, DRAM refreshed, system running in low power mode) using the
connected USB device. Set this jumper to pins 2-3 (+5VSB) to wake up the
computer from S3 and S4 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
3
2 2
1
PS2_USBPW
(Default)
+5V +5VSB