Asus P4B-FX - Manual (Page 40)

2-20 Chapter 2: Hardware information
Figure 2-25 Hard Disk LED Connector
2.8 Connectors
This section describes and illustrates the internal connectors on the
motherboard.
Do not place jumper caps over connector pins. Doing so may damage
your motherboard.
Always connect ribbon cables with the red stripe to Pin 1 on the
connectors. Pin 1 is usually on the side closest to the power connector
on hard drives and CD-ROM drives, but may be on the opposite side
on floppy disk drives.
1. Hard disk activity LED (2-pin IDELED)
This connector supplies power to the hard disk activity LED. The read
or write activities of any device connected to the primary or secondary
IDE connector cause this LED to light up.
P4B-FX
P4B-FX IDE Activity LED
TIP: If the case-mounted LED does not
light up, try reversing the 2-pin plug.
IDELED