Fiber Connector Types and How They Work

May 18, 2017 at 8:00 AM


There is no shortage of options available when it comes to fiber optic cables. We’ve discussed the different fiber terms, what they mean and how to read them. Now, we’ll take a closer look at fiber connector types.


There are numerous fiber optic connectors on the market today. The most common connector types are LC, SC, and ST styles.


ST – This connector type is still widely deployed in fiber networks. These connectors employ a bayonet style mount and cylindrical 2.5 mm ferrule that’s usually made of ceramic, but sometimes is constructed of metal or plastic. ST connectors are spring-loaded, so they must be properly seated/aligned to avoid high-loss.


SC - These snap-in connectors feature a 2.5 mm ferrule that keeps them secure in the port. The snap-in design latches with a simple push-pull motion. These connectors are available in simplex and duplex configurations.


FC – These connectors also use a 2.5 mm ferrule. They screw-in to connect firmly, though the key must be properly aligned in the slot before tightening. FC connectors were the most popular connector type for many years, but have largely been replaced by SC and LC connectors.


MT-RJ – These duplex connectors house both fibers in one polymer ferrule. They use pins for alignment and are offered in male and female versions. This connector type is not very widely used.


LC – These connectors use a standard ceramic ferrule. What sets theses connectors apart from other styles is that they are small form factor connectors that use a 1.25 mm ferrule and are half the size of SC connectors. LC connectors have been the most widely used interfaces in networking equipment over the past 10/15 years due to their small size.


All of these connectors are available in both Single mode and Multimode versions. ST, SC and FC connectors use the same 2.5 mm ferrule size, so they can me mixed and matched when connected using hybrid mating adapters as shown here:






There are three optional polish types that can be applied to fiber connectors: physical contact (PC), ultra-physical contact (UPC) or angled physical contact (APC). Each polish type provides a different level of back reflection, which is a measurement, in decibels, of the light reflected off the end of a fiber connector, and can be critical in some applications.


Click here to watch our video on fiber optic connector types.


For an in depth look at fiber connector colors, check out this blog post.


The Ultimate List of Fiber Cable Connectors and Colors

June 5, 2014 at 10:00 AM


You can practically see the rainbow when you look at our fiber cable offering on our website or in our catalog. 


In the world of fiber optics, there’s a standard color scheme to identify each and every type of fiber cable.  


And then there are all of those connectors to choose from… ST, SC, LC, MTRJ…


Though you may have heard of them, it can be challenging to identify the difference between each type of connector. 


We’re here to break it down. In the following tutorial, we’ll highlight some of the most common colors and connector types that you should be aware of. 


If you’re going to deploy a new network system using fiber or would like to better organize your existing fiber cables, you’ll want to stick around.




So what do they all mean?


Traditionally, the following jacket colors have been used to define Single mode and Multimode fiber cables:



9/125 Single mode



50/125 Multimode



(10 Gigabit Optimized)


Slate (Gray)

62.5/125 Multimode



Over time, the use of fiber has expanded in many applications and the need for different jacket colors has become a requirement for some customers. In today’s telecommunications networks you might also see different jacket colors used to denote different services or devices.


For example, if you have already allocated your traditional orange 50/125 cables to all of your high speed server connections, you can now add blue 50/125 fiber cables to denote WAN router connections.


By using colors to identify services/devices, troubleshooting is made easier, thereby decreasing network downtime. 


L-com has also developed a line of red, blue, green and yellow jacketed fiber cables which make port and service locations easier to find in dense equipment racks. 







In addition to the range of cable jacket colors, you can choose from an extensive variety of Fiber Optic connector types


The most common connector types you’ll see are: LC, SC, MPO and ST style connectors.


All of these types of connectors can be used with either Multimode of Single-mode fiber.


There are three types of polishes which can be applied to a fiber connector: PC or Physical contact, UPC or Ultra Physical contact and APC or Angled Physical contact.


Each polish type exhibits a different level of back reflection. Back reflection is a measure of the light reflected off the end of a fiber connector. This light is measured in decibels. For certain applications, the amount of back reflection on a fiber connector is critical.


L-com’s fiber connectors include commercial grade field installable fiber optic connectors as well as rugged IP67 fiber connectors for use in harsh environment applications.


In addition to our fiber connector video, check out one of the most popular technical resources we have- our Fiber Optic Connector Chart- that can help you find the fiber connector you’re looking for.




In addition to standard commercial and industrial connectors, there are also Keyed LC Singlemode 9/125 assemblies which have a variety of COLORED CONNECTORS.


L-com's Keyed LC line of Fiber Optic Cable Assemblies offers mechanical network security for organizations desiring to segregate networks due to privacy or security concerns. Each Keyed LC connector is color coded for identification and features a mechanical key which prevents users from accidentally connecting the cable to the wrong jack. 


There are a total of 12 colors available including: Brown, Cobalt, Gray, Magenta, Olive, Orange, Pink, Red, Turquoise, Violet, White and Yellow. These cables are OFNR rated to meet strict building codes and utilize Single mode 9/125 fiber. Match the color of the Keyed connector to the corresponding color of Keyed coupler to create a secure network connection. 


Do your eyes hurt yet?


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