This small, nondescript box on the exterior of homes serves as the final connection point for modern telecommunications services. Many homeowners often mistakenly refer to this utility box as the “internet box” or “cable box. ”Fiber internet works by sending data as beams of light through tiny glass strands (yes, really!). But your home devices — like your laptop, smartphone and smart TV — can't interpret light signals. An ONT device is critical in a fiber-to-the-premises (FTTP) or fiber-to-the-home (FTTH) setup. " What Does an ONT Do? Key Functions. But what exactly is it—and do you need one? An ONT, or Optical Network Terminal, is a device that converts fiber optic signals from your Internet provider into Ethernet signals that your devices can use. In short: ONT is part of a two-device setup; ONR is an all-in-one solution. Any standard router, including the primary unit of a mesh Wi-Fi system, will work at its full potential with any standard Internet broadband terminal.