“LOS” stands for Loss of Signal, and the red indicator typically shows that the fiber optic line isn't detected. Gently inspect the cable for physical damage and ensure it's connected properly; if the light remains red, reach out to your provider for a signal check. When it's green and steady, everything is fine. However, when it blinks red or stays solid red, it signifies a Loss of Signal, a problem preventing your router from communicating. The tables in this article provide detailed information about the possible appearances of the LED lights on each device, the possible causes of each state, and what you should do. Sometimes it may be due to a problem with your internet service provider, although you could also be experiencing this issue due to improper configuration of your router, a poorly connected cable, etc. Here you'll find out. If ON or blinking red: There is a physical fiber disconnection or cut, dirty connector, broken patch cord, or no signal from the provider. LAN Normal: Should flicker when a device is connected and active If OFF: No device connected, or the LAN port/cable may be faulty.
[PDF Version]