The installation process involves mounting the ONT and connecting it to a power source. There is no power in the fiber signal just light Most likely, the modem isn't designed to work with fiber, it probably sends out signals on coax or some other more traditional medium. The ONT is linked to your router or gateway using an Ethernet cable. * In some instances, the ONT. What equipment do I need for fiber optic internet? For a fiber optic connection, you need an optical network terminal (ONT), a router, and appropriate Ethernet connections for wired devices. Your service provider typically supplies the ONT, but you may need to purchase enterprise-grade routers and. Electricity from lightning, power surges, and static electricity cannot transmit across a fiber-optic line.