A Fiber Optic Termination Box is a small enclosure located at the terminal end of the fiber where it enters your customer premises. Through termination box couplers (adapters), pigtails and patch cords are connected. A typical PON topology (GPON, XGS-PON, or 25G PON) flows OLT → fiber distribution hub → passive splitters → distribution/drop fibers → premises. The number of ports in a fiber optic.