Do you know the function and connection of optical fiber connectors, pigtails, and terminal boxes?

Optical fiber as a transmission system is mainly composed of optical fiber jumpers, pigtails, terminal boxes, couplers and other equipment.

The following are the functions and connections of these optical fiber supporting equipment.

Optical fiber connector

Regarding fiber optic patch cords, the most commonly used fiber optic connectors are mainly the following 4 types:

SC-type connector

The SC-type connector has a rectangular shell, and the structural dimensions of the pin and coupling sleeve used are exactly the same as the LC connector. The SC connector jumper adopts a plug-in latch type fastening method, does not need to be rotated, the plug-in operation is very convenient, and the insertion loss fluctuation is small. It has the advantages of pressure resistance and high installation density. This kind of interface is more common in fiber optic transceivers!

LC-type connector

LC-type connector adopts modular jack (RJ) latch fastening method, plug and play, it is the most popular kind of optical fiber jumper, it can effectively reduce the use of space and is suitable for high density connection, this kind of interface is generally more common in optical modules.

FC-type connector

FC-type connector adopts the fastening method of turnbuckle, and the external reinforcement method is a metal sleeve, which is firmer after being inserted into the device, and the connector is not easy to fall off. Generally, it is used on the ODF side.

ST-type connector

ST-type connector shell is round, and the fastening method is turnbuckle.

Optical fiber pigtail

Only one end has a connector, and the other end is a broken end of an optical fiber core, which is connected to other optical fiber cores by fusion splicing. It often appears in the optical fiber terminal box to connect the optical cable and the optical fiber transceiver. It is also used between couplers, jumpers, etc. The classification of optical fiber pigtails is the same as that of jumpers. One jumper is cut into two pigtails.


The fiber coupler is a detachable connection device between the fiber and the fiber. It precisely connects the two end faces of the fiber so that the light energy output by the transmitting fiber can be coupled to the receiving fiber to the maximum extent and make it access the optical link to minimize the impact on the system. Commonly used fiber couplers mainly include SC fiber couplers, LC fiber couplers, FC fiber couplers, ST couplers, etc.

Terminal box

As the terminal equipment of the optical cable line, the optical fiber distribution frame shall have 4 basic functions.

①Fixed function: After the optical cable enters the rack, its outer sheath and reinforcing core must be mechanically fixed.

② Splicing function: After the optical fiber drawn from the optical cable is spliced with the tail cable, the excess optical fiber is coiled and stored, and the spliced joint is protected.

③Allocation function: plug the connector attached to the tail cable to the adapter, and realize the optical connection with the optical connector on the other side of the adapter. Adapters and connectors should be able to be flexibly inserted and removed; the optical path can be freely deployed and tested.

④Storage function: Provide storage for various cross-connected optical cables between racks, so that they can be placed in a regular and orderly manner.

The commonly used fiber distribution frames are mainly divided into 12 fiber distribution frames, 24 fiber distribution frames, 48 fiber distribution frames, 72 fiber distribution frames, 96 fiber distribution frames, etc.


Optical fiber transmission has the advantages of long transmission distance, strong anti-interference, and large bandwidth, and is often used in the communications industry. When using optical fiber as a link transmission system, it is also necessary to grasp the role of all accessories such as optical fiber jumpers, pigtails, optical fiber terminal boxes, couplers, etc., so that the implementation of optical fibers can be better in actual operation!

Post time: 2021-02-02


Lomoveishiy – Finland

I needed those to connect my PC on the third floor to have internet access in that room, and ISP installed their modem on the first floor only. After dropping fiber patch cables, plugged in all cables into these media converters at both sides, and link came up instantly. Was much easier than I thought!

Raymond – USA

Great experience – units worked straight out of the box – just needed plug in cables and we were done. I also like the possibility to enable jumbo frames, while we do not have a need for this feature at the current moment it’s great to have this option.

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