Will the light on the fiber optic cable be turned on when plugged into the router

Yes, when a fiber optic cable is properly connected to the ONT and the ONT is linked to your router, the corresponding lights on both devices should illuminate to indicate a successful connection.How the Connection WorksFiber optic cables do not connect directly to a standard home router because the signal is optical, not electrical. The fiber line terminates at an Optical Network Terminal (ONT), which converts light signals into electrical signals that your router can use . Once the ONT is powered and the fiber cable is securely connected, it communicates with your ISP's network. The ONT then outputs data via an Ethernet cable to the router's WAN or Internet port .Lights on the ONTPower Light: Indicates the ONT is receiving power. Green means normal operation .PON/Link Light: Confirms the ONT is connected to the fiber network. Solid green or blue indicates an active connection, while flashing or red indicates a problem .Data/ETH Light: Shows whether the ONT is transmitting data to a connected device, such as your router. Solid green means data is flowing .Alarm Light: Red indicates a fault or error; off means no errors .Lights on the RouterWhen the Ethernet cable from the ONT is connected to the router:WAN/Internet Light: Should turn solid green (or another color depending on the router) to indicate a successful Ethernet link .LAN Lights: May illuminate if devices are connected to the router's LAN ports.TroubleshootingIf the lights do not turn on:Ensure the fiber cable is fully seated in the ONT port .Verify the ONT is powered.Check the Ethernet cable between the ONT and router.Power cycle the ONT first, then the router .Contact your ISP if the PON or fiber signal light remains off or red .In summary, properly connecting the fiber optic cable to the ONT and linking the ONT to the router will trigger the relevant lights, confirming power, link, and data transmission.