Asus Z9NR-D12 - Manual (Page 42)

2-22 Chapter 2: Hardware information
6. Q-Code LED (LED1_LED2)
The Q-Code LED design provides you the 2-digit display, allowing you to
know the system status. Refer to the Q-code table below for details.
5. LAN LED (LAN34_LED1)
This LED indicates the connection status of LAN3 and LAN4.
The LAN LEDs function only when the motherboard is installed in a server
system.