Fan-out units are multiplier units or drivers that shift the functionality of one unit to multiple outputs. Thus, a repeater can have one output, but it can also be equipped with several, i.e. have multiple fan-outs. The advantage of fan-out technology is that all fan-outs have identical output characteristics.
The fan-out unit does not form a bottleneck in the network, as it does not affect the transmission speed for the individual connected devices in any way. Commercially available fan-out units allow the connection of four to eight end devices. Modular units also allow access to up to 32 connections. The connection from the end devices to the fan-out unit is made via normal transceiver cables, as is the connection of the fan-out unit to a transceiver on the Ethernet.
Fan-out units are also used to split ribbon cables with multiple fibers. These are connected to the fan-out unit via multi-fiber connectors such as the MPO connector or the MTRJ connector, where they are continued as single fibers. The fan-out can also be carried out via a fan-out cable, in which the multi-core FO cable is distributed to the single-core fan-out cables in a splitting unit.