These boxes protect delicate fibers from environmental and mechanical damage. Fast connectors and hardened adapters streamline the connection process, reducing signal loss and improving data. A fiber distribution box (FDB) is a passive enclosure that provides secure splicing, termination, and distribution of optical fibers. It typically contains splice trays, adapters, and cable routing components to manage fiber connections. The importance of a distribution box cannot be. In today's fast-paced digital world, fiber optic communication because of its high speed, large capacity and strong immunity to interference is the backbone of networks today.