Xiaomi router failed to connect to fiber optic cable

Xiaomi routers cannot connect directly to a fiber optic cable; an Optical Network Terminal (ONT) is required to convert the fiber signal to Ethernet for the router.Why Xiaomi Routers Cannot Use Fiber DirectlyMost Xiaomi routers, including models with WAN/LAN adaptive ports, are designed to accept Ethernet input, not raw fiber optic signals. Fiber optic cables transmit data as light pulses, which standard routers cannot interpret directly. To use fiber internet, the signal must first be converted into an electrical Ethernet signal via an Optical Network Terminal (ONT) provided by your ISP .Required Equipment and SetupOptical Network Terminal (ONT): Connect the fiber optic cable from the wall outlet to the ONT. This device converts the optical signal into Ethernet .Ethernet Cable: Use a Cat6a or higher cable to connect the ONT's LAN port to the Xiaomi router's WAN port .Router Configuration: Access the Xiaomi router's web interface (usually 192.168.31.1) and configure the WAN settings. Depending on your ISP, you may need PPPoE credentials (username and password) to establish the connection .Troubleshooting TipsCustom Mode Setup: If the router fails to detect the network cable, select custom mode (no network cable) during initial setup, then manually assign the WAN port in the router settings .Check ONT Functionality: Ensure the ONT is powered on and properly connected. If the router still cannot connect, try replacing the ONT .ISP Credentials: Some ISPs require PPPoE login information. Without these credentials, the router cannot establish an internet connection even if the physical connection is correct .Static vs Dynamic IP: Verify whether your ISP provides a static IP or requires dynamic IP configuration. Incorrect IP settings can prevent connectivity .Key TakeawayA Xiaomi router cannot directly use a fiber optic cable because it lacks the hardware to interpret optical signals. The correct setup involves an ONT to convert fiber to Ethernet, proper WAN configuration on the router, and, if required, PPPoE credentials from your ISP. Following these steps ensures your Xiaomi router can access fiber internet reliably.