Asus P4B266-C - Manual (Page 42)

2-20 Chapter 2: Hardware information
6. USB device wake-up (3-pin USBPWR01, USBPWR23)
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 sleep mode (no power to CPU, DRAM in slow refresh, power
supply in reduced power mode). Both jumpers are set to pins 1-2 (+5V)
by default because not all computers have the appropriate power
supply to support this feature.
The USBPWR01 jumper is for the rear USB ports. The USBPWR23
jumper is for the internal USB header that you can connect to the front
USB ports.
1. This feature requires a power supply that can provide at least 1A
on the +5VSB lead when these jumpers are set to +5VSB.
Otherwise, the system does not power up.
2. The total current consumed must NOT exceed the power supply
capability (+5VSB) whether under normal condition or in sleep
mode.
P4B266-C
®
P4B266-C USB Device Wake Up
USBPWR01
USBPWR23
+5VSB
2
3
+5V
1
2
+5V
1 2
+5VSB
2 3
(Default)
(Default)