Fiber in the loop
Fiber In The Loop (FITL) is a system implementing or upgrading portions of the POTS local loop with fiber optic technology from the central office of a telephone carrier to a remote Serving area interface (SAI) located in a neighborhood or to an Optical Network Unit (ONU) located at the customer premises (residential and/or business). Generally, 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 curb (FTTC), fiber to the node (FTTN), and fiber to the premises (FTTP).
Residential areas already served by balanced pair distribution plant call for a trade-off between cost and capacity. The closer the fiber head, the higher the cost of construction and the higher the channel capacity. In places not served by metallic facilities, little cost is saved by not running fiber to the home.
A similar network called a hybrid fibre-coaxial (HFC) network is used by cable television operators but is usually not synonymous with "fiber In the loop", although similar advanced services are provided by the HFC network.
The expression "Fiber in the Loop" was popularised by (possibly originated by) Robert Barrett through the company that he founded in 1999 called Fiber in the Loop a.k.a. FITL. Robert developed a One Gigabit Ethernet GBIC equipped add / drop mux that provided a user with four T1 / E1 ports and a 1GE customer equipment port. The equipment was developed as a piece of managed CPE (Customer Premise Equipment) for the "new-age" Ethernet Service Providers (e.g. Yipes / Telsion). The device was one of the first to use Circuit Emulation of T1 / E1 circuits using Ethernet packets / frames with accurate clock recovery and synchonisation. Robert's domain name www.fitl.com now used for a new venture in the cycling and fitness assessment sector - see entry for Formic Intelligent Training Labs.
Source: Robert Barrett
