Common Interfaces and Connectors in Fiber Optic Jumpers
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Common Interfaces and Connectors in Fiber Optic Jumpers

Posted on by FS.COM

According to the development trend, New methods for Computer Facilities or Mainframe network cabling have appeared. This is mainly manifested in the following respects.

1) In the host server room, switch routers and connecting lines have reached gigabit standards.

2) Using fiber optic jumper in connecting, SC interface has been eliminated. SC-SC interface is no longer being used. SC-LC interfaces are used with caution in some of the old switches. LC interface is mainly used, while based on the fiber network card replaced, LC-LC fiber jumper is basically used.

3) UTP cable has stopped being used. In the fiber-to-access layer switch, using all six jumpers.

4) ST fiber jumpers are still in use, but only over long distances, and used in conjunction with the fiber coupler.

Although the more single the host room line is, the more it is stable and easier to be managed, but for the common fiber interface and fiber jumpers, we should have a certain understanding.

Fiber optic connectors

FC: Round threaded (the most widely used on MDF)

ST: Snap-round

SC: Snap-square (mostly used on the switch routers)

PC: Micro-spherical polishing

APC: 8 degrees and micro-spherical polishing

MT-RJ: Square, one pair of fiber transceiver (used on Huawei 8850)

Fiber optic modules (general are hot-swappable)

GBIC: Giga Bitrate Interface Converter, using the optical interfaces of SC or ST

SFP: Small package SFP GBIC, using LC type optical fiber

Optical fiber

Single-mode: L, wavelength 1310; LH, singlemode long distance, wavelengths 1310,1550

Multimode: SM, Wavelength 850

Fiber optic interfaces

Fiber optic interface is physical interface that used to connect fiber optic cables.

ST (AT & T Copyright), is a most common connection device in multi-mode network. It has a bayonet holder, and a 2.5 mm long cylindrical ceramic or polymer ferrule to contain the entire fiber. ST is sometimes denoted “Stab & Twist”, very vivid description of the first insert and tighten.


FC is a most common connection device in the the single-mode network. It also uses 2.5 mm ferrule, but part of the FC connector is designed for the ceramic embedded in stainless card holder in the early time. Currently in most applications, FC has been replaced with SC and LC connectors. FC is an abbreviation of Ferrule Connector, indicating that the external reinforcement is made of a metal sleeve, and fastened with the turnbuckle.

SC also has a 2.5 mm ferrule. Unlike ST / FC, it is a plug-in device, widely used for its high performance. It is the TIA-568-A standardized connector, but is not widely used because the initial price is expensive (twice price of ST). SC is sometimes denoted “Square Connector”, because the SC is always square-like shape.

Fiber optic jumpers

Fiber jumpers are very important as switching devices and servers connected to the line. If there is no suitable fiber jumpers, the service is not going to work. Here are the main fiber jumpers types.

LC-LC: LC is the thread inserted in SFP(mini GBIC) which is used in the routers.

FC-SC: FC end is connected to the fiber optic cabling racks, and SC end to GBIC.

ST-FC: For 10Base-F connections, the connector type is usually ST, and the other end is connected with FC fiber optic cabling racks.

SC-SC: Both ends are connected to GBIC.

SC-LC: One is GBIC end, and another is SFP end.


On the label indicates of Pigtail connectors, we can often see the “FC / PC”, “SC / PC” and so on.

“/” the front part indicates the connector pigtail type

“SC” connector is a standard square connector, using engineering plastics, high temperature, not easily oxidized advantages. Transmission equipment sidelight SC connector interface is generally used.

“LC” connector has the similar shape with SC connector, but is smaller than the SC connector.

“FC” connector is a metal connector, usually used in the ODF side. The Pluggable times of metal connectors are more than plastic connectors.

More varieties of the signal connector, in addition to the above described three, there MTRJ, ST, MU and so on.

“/” Indicates that fiber optic connectors behind sectional process, that grind mode.

“PC” in the telecom operator’s devices are used widely, the joint cross-section is flat.

“UPC” the attenuation ratio “PC” to be small, generally used for devices with special needs, some foreign manufacturers jump fiber ODF of internal use is FC / UPC, mainly to improve the ODF device itself indicators.

In addition, “APC” model is the most application in early CATV broadcasting. It uses a pigtail head angled face, which can improve the quality of television signals. The main reason is that TV signals are analog optical modulation, and when the joint coupling plane is vertical, the reflected light back along the original path. Due to fiber index will once again return to the uneven distribution of the coupling surface, although energy is very small at this time but due to the analog signal is not completely eliminate the noise, so a clear equivalent in the original signal superimposed on a weak signal with a delay, performance on the screen is ghosting. Pigtail headband reflected light inclination can not return along the original path. General digital signal generally does not have this problem.

“SC” represents that the pigtail connector model is SC connector. Transmission equipment industry sidelight interfaces general use SC connectors. SC connectors are engineering plastics with good thermostability, and not easily oxidized; ODF side optical interfaces generally use FC connectors. FC is a metal connector. ODF does not have temperature problems, and at the same time the Pluggable times of metal connectors to more than plastic. Maintenance of ODF pigtail is more than the fiber optic pigtail.

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