Before connecting the cable, locate the fiber optic port on your router. It's typically labeled as “Fiber,” “ONT,” or “WAN” (Wide Area Network). To connect your fiber optic cable to a router, ensure you have the following: Fiber optic modem (ONT): Most fiber connections require an Optical Network Terminal (ONT), provided by your ISP. * In some instances, the ONT and the router are all in the same device, generally called a combo unit. * For larger homes, mesh. I know that "show cable-diag tdr int [slot/port]" command can check 10/100/1000 etherent link.