An Access Terminal Box is a protective enclosure used in fiber optic networks to house and organize fiber optic cables and splices. Here's what it is, why it's there, and what to do if you're switching provider or moving home. What is Openreach equipment in your home? Openreach builds and maintains the UK's broadband network. There are several lights on the ONT, when these lights change colour or flash, it means something is happening. It's where delicate strands are protected, splices are routed, connectors are exposed for patching, and future changes are made painless—or painful.