FITL(Fiber In The Loop) is an application of optical fiber transmission in access networks. The fiber optic lines placed in the pair of wires that run from the central office to the system at the customer location. In general, fiber is used in either all or part of the local loop distribution network. FITL can be implemented with any FTTX architecture, such as fiber to the cabinet (FTTC), fiber to the node (FTTN), and fiber to the premises (FTTP).
FITL system consists of the following elements: