Asus P4B-MX - Manual (Page 38)

2-18 Chapter 2: Hardware information
Figure 2-22 USB Device Wake-up Settings
2.7.2 Jumper settings
1. USB device wake-up (3-pin USBPWR)
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
sleep mode (no power to CPU, DRAM in slow refresh, power supply in
reduced power mode). This jumper is set to pins 1-2 (+5V) by default.
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. The total current consumed must NOT
exceed the power supply capability (+5VSB) whether under normal
condition or in sleep mode.
®
P4B-MX
P4B-MX USB Device Wake-Up
USBPWR
1 2 2 3
+5VSB +5V
(Default)