LC vs SC Fiber Connectors Defined and Analyzed in Detail

Fiber optic transmission technology has evolved over the years to meet the demands of high bandwidth and fast data applications. This is evident from the widespread use of fiber optic devices in data centers, LANs, and MANs. Fiber optic cables and connectors are the essential components of these networks. While fiber optic cables are often discussed, connectors are often overlooked. The topic of fiber optic connectors is comprehensive and may require multiple documents for discussion. This whitepaper focuses on two popular fiber optic connectors, SFP SC and SFP LC transceivers, which have gained significant popularity in recent years.
 
SFP Transceivers and Their Role in Modern Communication Applications
SFP, short for Small Form-Factor Pluggable, is an interface module used in communication applications. This transceiver can both receive and transmit data and can be used with both copper and fiber optic cables. In simple terms, it is a hot-swappable device that can be plugged into a network device's port. SFP transceivers support various communication standards such as Gigabit Ethernet, SONET, and fiber channels. They can be interfaced with LC and SC connectors, resulting in SFP LC transceivers and SFP SC connectors. The next section provides a basic overview of these connector types.  

What are LC and SC Connectors?

 

What is sfp LC ?

SFP LC stands for Small Form-factor Pluggable LC. It is a type of optical transceiver module used to transmit and receive data over fiber optic cables. LC refers to the type of connector used in SFP modules, which is a small, rectangular connector with a latch mechanism.
 
SFP LC modules are commonly used in networking equipment such as switches, routers, and network interface cards. They support various types of fiber optic cables, including single-mode and multi-mode, and different wavelengths depending on the application.
 
The SFP LC module is hot-swappable, meaning it can be inserted or removed from a device without powering it down. This flexibility allows for easy installation, upgrades, and maintenance in network environments.
 
 

What is sfp SC ?

 
SFP SC stands for Small Form-factor Pluggable SC. Similar to SFP LC, SFP SC is also an optical transceiver module used for transmitting and receiving data over fiber optic cables.
 
SC refers to the type of connector used in SFP SC modules. SC connectors are square-shaped and have a push-pull mechanism for easy insertion and removal. They are widely used in fiber optic networks.
 
SFP SC modules are compatible with various types of fiber optic cables, including both single-mode and multi-mode. They support different wavelengths, allowing flexibility in different network applications.
 
Just like SFP LC, SFP SC modules are hot-swappable, meaning they can be inserted or removed from a device without powering it down. This feature simplifies installation, upgrades, and maintenance in network environments.
 
 
SFP LC VS SC Connectors Key Differences and Similarities Discussed
Although LC and SC connectors are quite similar to each other in many ways, they differ in many other ways. The following pointers would help you understand it better.
Size of Ferrule:
The connectors are differentiated based on two different sized ferrules. The SC connector is equipped with a 2.5mm ferrule and LC connector with a ferrule of 1.25 mm. This along with a compact connector housing makes LC connector smaller than SC. This smaller footprint explains its increasing use in dense rack panels. LC connectors are a common sight in central offices with high packing density.
Ease of Use:
The SC connectors feature a snap-in connection that enables quick patching of cables into wall or rack mounts. Two SC connectors can be clipped using a reusable duplex holding clip to form a duplex SC connector. LC connectors feature a latch mechanism, which also ensures efficient removal as well as insertion. LC connectors can be easily grouped into a locking clip and keyed arrangement, which makes it popular.
Reduced Rearrangement:
LC connectors are equipped with anti-snag latches, which helps reduce the rearrangement caused due to cross-connection.
Insertion Loss and Return Loss:
Insertion loss is the ratio of power that is incident to the power that is transmitted by a connector or device. However, return loss refers to the ratio of power that is incident to the ratio of power that is reflected by a connector. LC connectors and SC connectors both have the same insertion and return loss.
Performance:
Both SC and LC connectors assure efficient, fast, and consistently strong performance, which leads to efficient data communication. Both these connectors assure interference-free data transmission.
Years of Utility:
Of these two connectors, the SFP SC transceivers are the oldest ones, as discussed before. These transceivers are quite popular and have been widely used over the years. However, SFP LC transceivers are gaining traction, too.
Time Saving:
As LC connectors are half-sized than their SC counterparts, which helps saves time for installation.
Repeatability:
Both LC and SC connectors possess polarization feature, which helps in maintaining or receiving direction, and ensures high repeatability.
Knowing the subtleties of LC and SC connectors would definitely help; however, you need to know about a few fiber optic devices that add value to any network. These devices serve as a base for connectors. Read the next section to know about these devices.
 

A Few Important Fiber Optic Devices to Connect LC and SC Connectors

The choice of LC and SC connectors will entirely depend on your application requirements. However, the following are a few devices that you may need while using these connectors.
Media Converters:
These devices enable signal conversion, and are largely used in networks that use both copper and fiber optic cables. There are copper to fiber, fiber to copper and fiber to fiber media converters to choose from. Nowadays, these converters are equipped with SFP transceivers, and they support LC and SC connectors.
Network Switches:
They are the most important network hardware, which connects different devices in the network. There are different types of network switches to choose from. Industrial switches, PoE switches, hardened switches, and so on are a few popular ones. Today, it is quite easy to find network switches with LC and SC SFP transceivers.
High Definition Transmitters and Receivers:
High definition serial digital interface (HD-SDI) is a standard for digital video transmission lines. These enable the transfer of unencrypted and uncompressed video and audio signals. HD-SDI converters, HDMI video systems, and HD-CVI, HD-AHD, and HD-TVI installation kits are examples of High Definition transmitters and receivers.
 

Summary

Present and future communication technology demand fast, efficient and safe performance in the data communication process. Large and complex databases all interconnected must be able to receive and transmit data without outside interference. Both SC and LC are designed to achieve such a kind of transmission. As for the question “SC vs LC: what’s the difference and which one is better?”, you just need to keep three basic points in mind:
1. SC has a larger connector housing and a larger 2.5mm ferrule.
2. LC has a smaller connector housing and a smaller 1.25mm ferrule.
3. SC used to be all the rage, but now it’s LC. You can fit more interfaces on line-cards, panels, etc with LC connector.
As we all know, the main difference between SFP LC and SFP SC transceiver lies in the connector. Among the different types of SFPs with LC connector, 1000BASE-SX SFP and 1000BASE-LX SFP transceivers are most commonly used. We take these two transceivers as an example. The 1000BASE-SX SFP LC transceiver is suitable for multimode fiber cables less than 550 meters. The LC SFP LX transceiver is suitable for 10km single-mode optical fiber cables and supports multimode fiber.
The 1000BASE-SX LC SFP transceiver standard is designed to support low cost multimode optical fiber operation in horizontal and short length backbone applications. The LC SFP LX transceiver standard is designed to support a longer multimode building optical fiber backbone network and a single mode campus backbone network. The cost of the LC SFP LX transceiver exceeds that of the 1000BASE-SX SFP LC transceiver.
 

Conclusion

Fiber optic communication is set to grow significantly in the years to come. It is making its presence felt in industries like defense, healthcare, railways, oil and gas, and so on. The choice of the right cables and cable connectors as well as fiber optic devices is important to ensure a precise connection. The pointers in this white paper will help when it comes to choosing between the SFP SC and SFP LC transceivers. However, if you are unsure about the right fiber optic devices, you can always get in touch with the team at VERSITRON, which is a market leader in fiber optics. The company provides various types of fiber optic devices such as copper to fiber media converters, fiber optic network switches, high definition transmitters and receivers, and so on.