ST: Developed by AT&T, this is a metal bayonet coupled connector, with a 2.5 mm ferrule, developed. The ferrule moves when a force is applied to the cable. There is a design of the ST connector, in which the ferrule does not move when the force is applied on the cable.
FC: FC connector is developed by NTT and has a metal screw on the connector and a 2.5 mm ferrule. The ruggedness of this connector is the reason for its extensive use at the interfaces of test equipment. It is also the most common connector used for polarization maintaining connections. There are currently four different specifications for the key width on FC connectors and for the slot width on FC adapters. Not all FC connectors will fit into all FC adapters. So, you need to be careful when selecting FC connectors and adapters.
SC: NTT developed this connector. This is a plastic push-pull connector, with a 2.5 mm ferrule. Push-pull connectors require less space in patch panels than screw on connectors. The SC is the second most commonly used connector for polarization maintaining connections.
LC: Lucent connector, which is developed by Lucent, is a small form factor plastic push/pull connector, with a 1.25 mm ferrule. The LC connector is popular in United States and Saudi Arabia. This connector has been referred to as a miniature SC Connector..
MTP: A push/pull ribbon connector, which holds up to 12 fibers. The 12-fiber capacity allows for very dense packing of fibers and a reduction in the number of connectors required. MTP connector is most suitable for ribbonized fibers. It is developed by NTT.
MT-RJ: A push/pull ribbon connector, which holds 2 fibers. MT-RJ connector is used in duplex cables. The idea of a two fiber connector is to support transmit and receive fibers in one connector.
MU: Developed by NTT, MU connector is a small form factor plastic push/pull connector, with a 1.25 mm ferrule. The MU has been referred to as a miniature SC Connector. The MU is very similar to the LC except that it is mainly used in Japan and other East Asian countries.
DIN: This connector is developed by Siemens and hence mainly used by Deutsch Telecom. A metal screw on connector, with a 2.5 mm ferrule, DIN connector his is suitable to use where the ruggedness of a metal screw on connector is required but where there is not enough space for a FC Connector.
E2000: Developed by Diamond, this type of connector is a plastic push-pull connector, with a 2.5 mm ferrule. The built in dust cap always stays on the connector protecting the ferrule and blocking harmful laser light when the connector is disconnected.