This guide explains how to evaluate fiber termination box capacity correctly, including fiber count, port configuration, splitter accommodation, and future growth. Many buyers assume “capacity” simply means the number of adapter ports on the front panel (for example, 8 ports or 16 ports). What Is a Fiber Termination Box in an Apartment FTTH Network? In an apartment building, a. Fiber termination box (FTB), also known as optical terminal box (OTB), generally refers to a distribution box specially designed for fiber cable management (fiber patch cables/pigtails) in FTTH applications. It helps protect fragile fiber optic terminals and helps create a simple system to manage output and input cables.