These boxes are commonly used in indoor applications, such as in homes, offices, and data centers. Whether you go for an indoor or outdoor installation can impact your internet's reliability, speed and even how easy it is to troubleshoot issues. Let's break it all down, so you can make an informed choice and get the most out of your fiber experience. What is an ONT? Think of the ONT as a. In fiber-to-the-home (FTTH) networks, fiber optic termination boxes are essential enclosures where cables are spliced, protected, and routed toward end users.