Fiber connectors are used to terminate the end of an optical fiber. They allow optical fibers to be connected and disconnected quickly and safely, but most importantly, they align fiber cores for light to pass from one optical fiber to the other. Using connectors also allows you to introduce local maintenance and testing, and the possibility of easily reconfiguring, connecting, and disconnecting your network.

Nowadays fiber optic connectors come in several varieties, including SC, ST, LC, FC, MTRJ, E-2000, MU, MPO/MTP, etc. But what do they do, and what are they for? Here lists the history of different fiber optic connector types, which could probably make some help.



Generic Specification for Fiber Optic Connectors
Fiber Optic Connector Intermateability Standards (FOCIS)
TIA/EIA-568-B.3 /C.0 /C.3
Commercial Building Fiber Optic Standards


Generic Requirements for Single Mode Optical Fiber Connectors
Generic Requirements for Multi-fiber Optical Connectors


BICONIC Connector LSA (DIN) Connector FDDI Connector

BICONIC Connector (FOCIS 1)

The Biconic connector was developed by AT&T and became the de facto standard for long haul telecommunications.
The Biconic connector features a cone-shaped tip, which holds a single fiber.
It is non-metallic, using polymer and epoxy in its construction.
Telcos have long since adopted other connectors, mainly the SC due to the drawbacks of the Biconic such as its large size and the fact that it is mated by screwing into its coupling.
Screw coupling makes its performance sensitive to rotational changes.

LSA (DIN) Connector 

The LSA connector is known as DIN fiber optic connectors, which are precision machined and feature a spring loaded floating zirconia ferrule. This compact and unique connector offers great reliability and superior performance.

FDDI Connector 

Media Interface Connector (MIC) also known as FDDI (Fibre distributed Data Interface) connector. The FDDI connector is born a duplex with push-pull structure for quick and easy operation. FDDI features the three keys for versatile assignment in the networks and its ferrule is 2.5mm.


ST Connector SMA905 Connector SC Connector FC Connector MTRJ Connector

BFOC (ST) Connector (FOCIS 2)

The Bayonet Fibre Optic Connector (BFOC) also known as Stick and Twist (ST) connector. ST connector is the oldest design of the connectors still in common use. The ST connector was one of the first connector types widely implemented in multimode fiber optic networking applications (rarely single mode). Although extremely popular for many years, the ST connector is slowly being supplanted by smaller, denser connections in many installations.

SMA905 Connector

F-SMA/SMA-905 (SubMiniature A) is a non-contact design for multi-mode and POF fibers with large core diameters.

SC Connector (FOCIS 3)

The SC connector was developed (in Japan by NTT) to eliminate having to screw and unscrew the connector every time and to reduce the cost by molding instead of machining the connector. A big advantage of this push/pull connector over a FC connector is that less room is required between connectors on patch panels.

FC Connector (FOCIS 4)

The FC connector is improved on the ST connector by isolating cable tension from the ferrule, keying the location of the ferrule for angle polishing, and threading onto the adapter for a more positive connection. FC was one of the most popular single mode connectors for many years but is been mostly replaced by SC and LC connectors which will be mentioned next.

MT (MTRJ) Connector (FOCIS 12)

The MTRJ connector (or MT-RJ, stands for Mechanical Transfer-Registered Jack) was then developed to put transmit and receive fibers into one connector. This was the first connector to use the MT ferrule design as opposed to a 2.5 mm or 1.25 mm diameter ferrule. The MTRJ connector closely resembles an RJ-style modular plug, even getting part of its name from the resemblance. Please note that the MTRJ connectors are always duplex in that they hold two fibers.


ESCON Connector MPO Connector LSH (E2000) Connector MU Connector

ESCON Connector

The ESCON (Enterprise Systems Connection) is a data connection created by IBM to used to connect their mainframe computers to peripheral devices.

CF08 (EC) Connector

The CF08 connector also known as EC connector. Its high performance, very low reflexion rate and its very economical design make the EC connector the most adapted to the requirements of the subscriber networks of the 21st century.
The EC connector is also the first link in a coherent and evolutionary system.

MPO Connector (FOCIS 5)

The MPO (Multi-fiber Push-On) connector is defined by two different standards. International the MPO is defined by IEC-61754-7. In the USA, the MPO is defined by TIA-604-5 (FOCIS 5). The MTP (Multi-fiber Termination Push-on) connector is a US Conec’s trademarked name for their MPO connector.
The MTP connector is fully compliant with both FOCIS 5 and IEC-61754-7; therefore it is an MPO connector. MPO/MTP was then developed to increase fiber density even more. The MTP has 12 or 24 fibers in its MT ferrule. Because of the high number of fiber strands available in a small connection, MTP/MPO fiber assemblies are used for backbone, cross-connect, and breakout applications.

LSH (E2000) Connector (FOCIS 16)

The LSH (E2000) connector was developed as an improvement on the SC connector design. It has a push-pull latch that retains the connector, a dust cap always in place, and a smaller size. Note: E2000 is a trademark of Diamond SA, Switzerland.

MU Connector (FOCIS 17)

The MU connector was developed by NTT, and it has the same push/pull style, but can fit two channels in the same footprint of a single subscriber connector. The connectors are composed of plastic housing and φ1.25mm Zirconia Ferrules. These products, called as "mini SC," have high reliability and operationally same with SC connectors and adapters.


VF45 Connector LC Connector VSFF Connector CS Connector SN Connector MDC Connector

VF45 Connector (FOCIS 7)

The VF45 (Volition) connector, designed by 3M, was a duplex fiber connector primarily intended for fiber-to-the-desk LAN application.

LC Connector (FOCIS 10)

The LC connector is a small form factor (SFF) fiber optic connector. The LC connectors use a 1.25mm ferrule, half the size of the ST. It was developed to reduce the space required for connectors on patch panels as the patch panel densities increased. LC connector was developed by Lucent Technologies (Alcatel-Lucent for now) and uses a retaining tab mechanism and the connector body resembles the squarish shape of SC connector.

VSFF Connector (CS connector, SN connector and MDC connector, MMC connector)

The Very Small Form Factor (VSFF) Fiber Optic Connectors is the next-generation connector for fiber optics, especially the high-density data center cabling network. It is short for a very small form factor connector, compared with traditional SFF connector (Small Form Factor connector) like Duplex LC and MTRJ, etc, it is much more compact. It utilizes a reduced ferrule pitch to enable a smaller connector housing to allow a density increase in fiber optic cabling.
Currently, the VSFF connector family includes CS connector, SN connector, MDC connector and MMC connector.


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