You'll typically find an Optical Network Terminal (ONT), or fiber box, in a central part of your home, like on the outside of your home, in your garage or even in a closet, and it plays a vital role in bringing fiber internet to your household via your internet service provider. The ONT is a unit. 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. It's a key part of any Fiber to the Home (FTTH) setup. If your home uses cable Internet instead of fiber, you don't need an ONT.