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Demystifying the Fiber Access Terminal (FAT) Cabinet
Fiber access terminal (fat) also known as fiber distribution hubs (FDHs), are a critical component of fiber-to-the-premises (FTTP) communication networks. These outdoor cabinets may be mysterious units to the average consumer, but they serve an important role in delivering high-speed fiber optic connectivity. This article will demystify what goes on inside these fiber hubs and explain their function in an FTTP network.
A FAT cabinet is essentially the junction point where the fiber optic cable from the service provider meets the local distribution network. By terminating the fiber connections at the FAT, the service provider can efficiently distribute the fiber strands to numerous customer locations in the area via fiber optic splitter trays and patch panels inside the terminal.
The FAT contains modular components to divide and allocate the incoming fiber capacity. Splitter trays utilize optical splitting technology to break out the fiber strands into multiple ports. This allows a single fiber strand to be shared among multiple customers in a split ratio like 1:16 or 1:32.
Patch panels inside the FAT allow the provider to cross-connect individual fiber strands to specific customer drop cables based on location. By doing this, the FAT enables a portion of the input fiber capacity to be assigned flexibly across different households and businesses in a neighborhood.
Hardened FAT enclosures are weather and tamper resistant to protect the internal fiber optic splitters, connectors, splices and patches. The terminals are mounted on concrete pads or poles readily accessible for technicians to upgrade service. The modular design also allows capacity to be added incrementally as new customers come online.
For customers, the FAT is the connection point where the provider’s fiber network ends, and the simple drop cable to the customer premises begins. All the behind-the-scenes fiber management happens out of sight inside the FAT. Demystifying these fiber hubs helps appreciate how FTTP providers efficiently deliver blazing-fast broadband speeds over a passive optical network.
