You can't directly connect a fiber optic cable to your router. You need an intermediary device. The fiber line terminates at the Optical Network Terminal (ONT), which is typically supplied and installed by the internet service provider. This specialized equipment serves as the. Depending on the chassis, you can use Quad Small Form-Factor Pluggable Plus (QSFP+), QSFP28, SFP28, and RJ-45 connectors to connect the ports on the router to other network devices. Check compatibility: Before you begin, make sure your router supports fiber optic connection.