Written by Ben Hamlich, Director of Technical and Product Innovation at trueCABLE RCDD, FOI
In the world of copper-grade Ethernet cables, very little has changed in terms of how they are terminated over the past 20 years. Whether it’s the late 90s or today, you’ll see 8P8C RJ45 connectors At the end Ethernet patch cords and Cornerstone cranes Mounted in walls that belong to Patch panels. the Color code T568A and T568B It also remained the same, dictating the color code sequence of the wires to make the proper connections. One of the main things about a copper Ethernet network is that it is almost impossible to connect it directly if you need to extend it. You have to terminate it in some way (connector, patch panel, etc.) in order to get from point A to point B while observing fairly strict rules Length restrictions.
Stretching and eventually terminating a fiber optic cable is completely different from a copper Ethernet cable. Initially, if the installer needs to extend fibers that do not need to be connected or separated, the fibers will be joined together (either fusion or mechanical splices). During installation at the point where the fiber cable must be connected and/or disconnected, you need to switch your strategy and place a connector of some sort. Fiber optic cables have undergone a significant evolution in connectors, and none of these connector styles are compatible with each other. Some types of connectors are already being phased out. The interesting thing about fiber optic connectors is how you choose which connector to use. The choice depends largely on the equipment requirements and to a lesser extent the installation environment.
In this blog we will cover:
Simple vs Duplex Connector assembly patterns
FC, SC, LC, ST and MPO/MTP connectors
Simplex vs duplex
In order to understand the different types of connectors that exist, we must first talk about assembly styles. Connectors come in two different basic assembly styles – simplex and duplex. This sounds very complicated but it is not. Simple = single and double = double. A simplex connector is simply one connector terminated on a single fiber. A dual connector is basically two single connectors side by side, often in a plastic assembly. Dual mode fiber optic cord is related to the term “compressed cord” and that literally means two patch fiber cords joined together in the vest and can be separated…or unzipped, I guess? That’s the term and it stuck, so we’ll follow it. What determines whether you use a simplex or duplex style connector is your endpoint equipment and how you connect things. It should be noted that simplex and duplex have nothing to do with single mode, multimode or the actual connector type such as LC or SC. The key point is that no matter which assembly we’re talking about, a single connector terminates a single strand of fiber.
Here are some pictures to illustrate the idea:
The dual connector assembly is on the left. The simple one is on the right. Both are LC.
FC connectors
FC connector (seen connected to single-mode fiber in duplex configuration)
The FC connector has been around for some time and is the oldest form of fiber optic connector. The abbreviation FC means “Ferrule Connector” but is often used as an abbreviation for “Fiber Channel” as well. This screw connector is made of metal and is very safe against vibration and accidental disconnection. The closest counterpart in the world of copper cables is the F-Connector seen on coaxial cable. FC connectors use a connector key and must be inserted carefully to avoid scratching the end face of the fiber. This connector has fallen out of favor due to improvements in connector technology and the costs associated with precision-made metal connectors. In this field, it is still seen in industrial and robotic applications where reliability is of paramount importance. FC connectors use a 2.50mm ferrule.
SC connectors
SC connectors are probably the most common fiber connector in use today, but they are quickly being overtaken by the much smaller LC connector as SC connectors are not suitable for very high density applications. SC is short for “Subscriber Connector” and it means that literally. The connector is often terminated by the fiber coming to a home or business (the end subscriber). It has also been called the “standard conductor”. Man, everything has multiple names here!
The SC connector shown in a simplex format is terminated on single-mode fiber
SC connectors are of the plastic push-pull type, attached with a tab. There’s no fancy stabilization mechanism here, nor need there be. SC connectors are vibration-resistant and moderately pull-resistant (but not vibration-resistant) while being easy to connect or disconnect. There is less risk of damaging the fiber end-face during connection/disconnection compared to FC. The biggest downside to these connectors is size. Like FC connectors, SC connectors use a 2.50 mm ferrule.
LC connectors
SFF (small form factor) connectors are very popular these days, and for good reason. Its much smaller size allows for high density installations. Insert the LC connector. The abbreviation LC means “Lucent Connector” but of course everyone just says LC. Like the SC connector, this type of connector is switched, vibration-resistant, and made of plastic. Unlike SC connectors, the LC connector is completely pull-resistant due to the positive latch and is about half the size. LC connectors use a 1.25mm ferrule.
SC connector on the left. LC connector on the right. Big difference!
LC connectors are often used with optical fibers Transmitters and receivers They are hot-pluggable devices that can be connected to an Ethernet switch that has SFP/SFP+ ports. The job of the transceiver is to translate electrical signals into optical pulses, and this strategy offers great versatility.
Quick comparison between LC and SC connectors
LC and SC are the most common fiber connectors in use today. What is the difference between SC and LC connectors? Here’s a quick comparison to help differentiate them.
LC transceivers
LC transceivers. These are 10 Gigabit multi-mode.
An Ethernet adapter manufacturer often does not include transceivers because the transceiver you need will depend on the fiber optic cable you intend to install, often driven by the length or speeds involved. This has the effect of lower switching prices initially. In all of the above types of installations, the endpoint equipment has a built-in optical transmitter, resulting in higher costs and the need to have many different versions of the same piece of equipment, supporting different types of fiber technology. Transceivers and LC connectors provide modularity and flexibility, because switching from MMF at 1G and 1,500 feet to SMF at 10G and 4,000 feet can be as simple as switching to lower-cost transceivers and using a different cable rather than replacing the cable. The whole switch!
The end result is that the LC connector and transceiver strategy is transforming the fiber optic market in many unprecedented ways, such as bringing the technology directly to the local market and the small manual installer.
ST connectors
The last type of connector we’ll talk about that is intended for a single strand of fiber is the ST connector. ST is an abbreviation for “Straight Tip”. This type of connector is metallic and uses a bayonet-shaped plug and socket. Essentially, this means that the connector is twisted and closed (but not physically clamped) like the common BNC connector used in audio/video applications (often seen used on coaxial cable).
ST connectors are on the left. The dual SC set is on the right for comparison.
ST fiber connectors are not resistant to pull or vibration and are arguably the least reliable way to terminate a strand of fiber. They are not used much anymore, having been replaced by superior connectors such as SC and LC. ST connectors use a 2.50mm ferrule like FC and SC.
MPO/MTP connectors
Until now, we’ve been talking about connectors that terminate on a single fiber strand. Are there connectors that allow large numbers of leads to be connected at once? Oh yes, yes there is. One common strategy for running fiber optic cables is to take a 12 or 24 fiber distribution cable into a communications room (TR), and then you can do a number of things to terminate this distribution cable so you can install it in your equipment:
Pull a high-fiber cable that has only disconnected fibers hanging from the end and then mechanically fuse or splice each fiber individually to a “pigtail” outside the fan that is already connected to the SC or LC connectors on the other side. This is a tedious process, which increases the possibility of errors.
Drag in a Pre-connected high fiber count cable (MPO/MTP connector already terminated) Then simply connect it to the fan output cable which has an MPO/MTP connector on one side and anywhere from 12 to 24 SC or LC connectors on the other side. It’s factory made, and ready to use! Welcome delivery and prayer (… oops, I meant He plays)
MPO connectors represent Multi Fiber Push On Technology, an industry recognized and defined connector style. MPO connectors come in male and female styles. MTP connectors fall under the MPO umbrella but are actually a trade name. All MTPs are MPOs, but not all MPOs are MTPs since “MTP” is a registered trademark of US Conec. MTP stands for Multi Fiber Termination Pressure. MTP connectors are essentially the same idea but have improvements such as a more secure locking mechanism and more precise fiber alignment. They both work the same way and allow two rows of 12 fibers (up to 24) to be connected at the same time. Of course not everything MPO patch cords She is the same. There is MPO > MPO as well. It all depends on the installation and equipment. Here are some examples:
MPO > MPO cable on the left. MPO > LC connector fan outside on the right.
So, there you have it. This is a quick overview of the various connector styles that you may or may not be familiar with. The vast majority of the time, you will encounter SC, LC or MPO connectors as the other connectors are used less and less. We haven’t talked about the ultimate face polishes (PC, UPC, APC) Nor the standard Color coding Being to help distinguish between these cables. This will be a future blog! For now I will say…
Happy communication!
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