Compared to Copper cables, Fiber connector types are incredibly varied. Where copper twisted pairs tend to terminate with an RJ45 plug, fiber optic connectors come in all sorts of shapes and sizes, with all manner of different use cases in mind. The fiber connector types, sometimes referred to as terminations, link fiber optic cables together through terminals, switches, adapters, and patch panels, by bridging the gap between their internal glass fibers that transmit the data down the length of the cable.
They need to be incredibly precise, so despite the many different fiber connector types, all fiber optic cable connectors are built to a high standard – though some are designed with higher-performance targets in mind, and others are built to a more durable standard.
Here’s everything you need to know about the different options out there for fiber optic connections.
Why Different Connectors Exist
There are a few different reasons why there are so many different kinds of fiber connector types. The first is that there are simply different cables for different jobs. There are connectors designed for single mode and multimode fiber optic cables. There are connectors designed to offer greater in-socket stability, so they cannot easily fall out or be pulled free when in place. There are connectors which have dual (duplex) connections, and others with single (simplex) connections. There are connectors which are designed to be more durable or offer greater protection for the cable itself, such as having a longer boot, and there are others which don’t, with shorter boots. There are smaller, and larger connectors, too.
The fiber optic cable standards have changed over the years, too, leading to newer, more advanced connectors. Different manufacturers have also made attempts at creating new standards, and when they have received some adoption, but not full compliance across industries, that results in an even greater number of available connectors. Some of which do much the same job as each other, but in slightly different ways.
Fiber Optic Connector Types
There are many, many different fiber connector types, and to list all of them would make this article far too long and indigestible. Instead, here are some of the most prominent, most important, and most widely available fiber optic connections you can buy and utilize today, including an explanation of why you might want to use one over the other.
Lucent Connectors (LC)
Lucent Connectors, typically known as LC connectors, were developed by Lucent Technologies as a small form factor solution to fiber optic connections. They have some of the smallest ferrules at just 1.25mm thick, making them a small-form-factor fiber connector type. Their size, square shape, and duplex header design make them ideal for heavily populated patch panels and cabinets where packing in as many connections as possible into a tight space is the goal.
It’s one of the most commonly used fiber optic connections today and works with both multimode and single-mode cables. Cables fitted with LC connectors are fairly difficult to remove once plugged in, making them one of the more sturdy cable connector standards. However, that can prove problematic as their small form factor encourages dense packing in patch panels and data cabinets, which can make deliberately removing individual LC connector fiber cables quite difficult. To help with that, some network administrators will use an LC connector extraction tool which makes the process a little easier.
Standard Connectors (SC)
SC connectors were developed by the Japanese telecoms company, NTT, and though the original name may have been “Subscriber Connector,” they’re colloquially known as Standard Connectors or SC Connectors. They’re a square-shaped, duplex connector that uses a 2.5mm ferrule and has a push-pull mechanism to latch them in place. This makes them more robust than other connectors, like ST connectors, so the signal won’t be interrupted if the cable is pulled.
This is an older connection that is slowly being replaced but has been a standard for long enough that it has seen extensive usage in networks all over the world. While its square shape does make it useful for fitting into smaller spaces, more modern, leaner connections like LC connectors, have proved more effective and space-saving, so are seeing greater use in newer network rollouts.
ST connectors were developed by AT&T and were one of the first fiber connector types to see widespread adoption in fiber optic networks all over the world. The Straight Tip (ST) design has a 2.5mm ferrule, the same as SC connectors, and can be used interchangeably with that alternative connector type when using a hybrid adapter.
It features a spring-loaded, half-turn bayonet-style lock that makes it quick and easy to attach and detach, all whilst providing additional security against accidental disconnects. It’s not foolproof, with other fiber connector types offering a more robust connection, but it’s still useful. It isn’t the best solution in tighter patch panels and cabinets, either, where it can be hard to get the purchase necessary to perform the unlocking turn.
Typically used with multimode fiber optic cables, ST connectors see a lot of usage in legacy networks, although they are slowly being replaced by newer cables.
Ferrule Core Connectors (FC)
FC connectors are so named because they were the first to be built with a ceramic ferrule with a stainless steel screw mechanism for attachment. This is in stark contrast to the plastic bodies of most other fiber connector types, like SC, and LC connections. FC connectors are designed to provide a much more robust connection that is almost immune to accidental removal, thereby guaranteeing there won’t be any interruptions in the data.
The keyed screw connection with FC connectors does mean that installing and uninstalling them takes extra effort, and they aren’t as well suited to tighter spaces where you can’t get enough purchase to complete the screw mechanism. However, that inconvenience can be worth it when the sanctity of the connection is most important.
Mostly used with single mode fiber optic cables, FC connectors are commonly used in networks designed to transmit consistent information, such as video streams, where any drop in the data connection would cause an immediate and obvious interruption of the data. They are, however, seeing reduced use in newer networks, with administrators preferring the ease of use with LC and SC connectors.
Multi-Position Connectors (MPO)
MPO connectors, sometimes marketed interchangeably with MTP connectors, are simplex fiber connector types with a push/pull latch system that locks them into place. While MTP is largely a branding choice rather than a distinct connector type, the connectors were designed with higher-performance networks in mind, while MPO connectors are more commonly marketed toward less demanding applications. Both fiber connector types work with single mode and multimode cables – the ferrule is slightly angled on single mode cables – though they see the most usage in high bandwidth multimode cables, due to the way the connector combines up to 24 glass fibers within a single rectangular ferrule.
MPO/MTP connectors are particularly complicated to use due to potential issues with polarity arising from misconfigured cabling. Network administrators need to make sure they use the right configuration of cables to avoid any problems with signal transmission.
Mechanical Transfer-Registered Jack (MTRJ) connectors are duplex connectors developed by AMP/Tyco and Corning. They use pins for alignment and come in both male and female guises. It has a plastic body with a tubular locking mechanism to hold it in place once connected. They are one of the least common fiber connector types used today, though still see some use in legacy systems and networks.
With a small ferrule, MTRJ connectors have seen use in the past in more compact patch panels and cabinets, and have mostly been used with multimode cables. Today, however, there are plenty of alternatives which network administrators usually gravitate toward instead.
Fiber Optic Connectors by Cable Matters
Cable Matters offers a wide range of different fiber optic cables for all uses and needs; that includes a wide range of cables with different connector types, and different adapters to help you connect those cables to any patch panels you need, or directly to other cables.
You can buy LC to LC duplex OS2 cables at a range of lengths for a cable that’s ready to use right out of the box. You can connect multiple LC fiber optic cables with our LC to LC duplex fiber optic adapters, too. We also offer MPT female to LC duplex cables and multimode LC to SC fiber optic cables, for bridging different fiber connector types together.
If you’re looking to build a patch panel to receive all manner of fiber optic connections, you’ll need a collection of keystone jacks that are the right form factor for your cables. Cable Matters can provide patch panels with LC and other connector types pre-fitted. Alternatively, you can opt for a rack or wall mount blank patch panel and then install any kind of keystone jacks that you like. Cable Matters offers both LC and SC multimode fiber keystone jacks in different colors and quantities, to cater to every need.