Asus P5QC - Manual (Page 48)

2-22 Chapter 2: Hardware information
3. USB device wake-up (3-pin USBPW1-4, USB7-10, USB1112)
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 USBPW1-4 jumper is for the rear USB ports. The USBPW7-10 and
USBPW1112 jumpers are for the internal USB connectors that you can
connect to additional USB ports.
• 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.
2. Keyboard power (3-pin PS2_USBPW56)
This jumper allows you to enable or disable the keyboard and USB port 5-6
wake-up feature. When you set this jumper to pins 2-3 (+5VSB), you can
wake up the computer by pressing a key on the keyboard (the default is
the Space Bar) or using a USB device. This feature requires an ATX power
supply that can supply at least 1A on the +5VSB lead, and a corresponding
setting in the BIOS. The USBPW56 jumper is for the internal USB connectors
that you can connect to additional USB ports.