Asus RS720-E7/RS12 - Manual (Page 66)

4-14 Chapter 4: Motherboard information
11. System panel connector (20-1 pin PANEL1)
This connector supports several chassis-mounted functions.
(1) System power LED (3-pin PLED)
This 3-pin connector is for the system power LED. Connect the chassis
power LED cable to this connector. The system power LED lights up
when you turn on the system power, and blinks when the system is in
sleep mode.
(2) Message LED (2-pin MLED)
This 2-pin connector is for the message LED cable that connects to
the front message LED. The message LED is controlled by Hardware
monitor to indicate an abnormal event occurance.
(3) System warning speaker (4-pin SPEAKER)
This 4-pin connector is for the chassis-mounted system warning
speaker. The speaker allows you to hear system beeps and warnings.
(4) Hard disk drive activity LED (2-pin HDDLED)
This 2-pin connector is for the HDD Activity LED. Connect the HDD
Activity LED cable to this connector. The HDD LED lights up or flashes
when data is read from or written to the HDD.
(5) Power button/soft-off button (2-pin PWRSW)
This connector is for the system power button. Pressing the power
button turns the system on or puts the system in sleep or soft-off mode
depending on the BIOS settings. Pressing the power switch for more
than four seconds while the system is ON turns the system OFF.
(6) Reset button (2-pin RESET)
This 2-pin connector is for the chassis-mounted reset button for system
reboot without turning off the system power.