Asus RS320Q-E7/RS12 - Manual (Page 62)

4-14 Chapter 4: Motherboard information
4.4 Internal LEDs
1. Standby Power LED (SB_PWR1)
The motherboard comes with a standby power LED. The green LED lights up to
indicate that the system is ON, in sleep mode, or in soft-off mode. This is a reminder
that you should shut down the system and unplug the power cable before removing or
plugging in any motherboard component.
2. Baseboard Management Controller LED (BMC_LED1)
The green heartbeat LED blinks per second to indicate that the ASMB5 is working
normally.
The heartbeat LED functions only when you install the ASUS ASMB5.