Asus M4A78-AM - Manual (Page 30)

2. Keyboard/mouse power (3-pin KBPWR)
This jumper allows you to enable or disable the keyboard/mouse 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), clicking the mouse. This
feature requires an ATX power supply that can supply at least 1A on the +5VSB lead,
and a corresponding setting in the BIOS.
3. USB device wake-up (3-pin USBPW1-4 and USBPW5-10)
Set this jumper 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). This jumper is for the
internal USB connectors that you can connect to additional USB ports.
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