Fiber Termination Box, also known as FTB, typically consists of two main parts: the outer shell body and the adapter tray that protects the fiber connector points. This ensures the components are safeguarded against damage during operation and placement. Importance of Durable. In every fiber build, there's a quiet place where the glass path meets the real world: the fiber optic terminal box. It's where delicate strands are protected, splices are routed, connectors are exposed for patching, and future changes are made painless—or painful. Choosing the right fiber optic. A fiber terminal box, also known as a fiber distribution box, is a device used in fiber-optic communication networks to terminate, splice, and distribute optical fibers.