After the communication engineers complete the optical fiber splicing in the fiber splice enclosure box, they need to coil the optical fibers one by one so that they cannot have excessive bending angles that will affect normal telecommunication. The connection of optical fibers must go through multiple fiber splice closure. Splices are generally placed in a splice tray which is then placed inside a splice closure or. FOSC, or Fiber Optic Splice Closure, is a specialized protective enclosure specifically engineered to safeguard fiber optic splices – the critical junction points where individual optical fibers are permanently joined together. Whether underground, aerial, or in manholes, splice closures are the first line of defense against environmental threats to your fiber. Fiber optic splice closures play a role here.