What is the difference between LC and SC connectors?

LC connectors have a smaller 1.25mm ferrule and are suited for high-density applications, while SC connectors use a 2.5mm ferrule and are commonly used in telecom systems.

Are ST connectors still used today?

ST connectors are mainly used in legacy multimode networks and are being replaced by LC and SC in modern setups.

Which connector is best for data centers?

LC and MTP/MPO connectors are preferred in data centers due to their compact design and support for high-bandwidth applications.

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LC vs SC vs ST Fiber Connectors: Types, Differences, and Applications

LINK-PP Official 　·

Aug 07,2025

Choosing the right fiber connector is essential for building a high-performance network. This guide breaks down LC, SC, ST, FC, and MPO/MTP connectors to help you decide the best fit for your application.

Optical Fiber connector types of LC, SC, FC, ST, MTP

What Is a Fiber Optic Connector?

A fiber optic connector aligns and joins two fiber ends to allow light to pass with minimal loss. They are designed for low insertion loss, easy connection/disconnection, and mechanical stability. The right connector ensures network efficiency, especially in data centers, FTTH, and telecom environments.

LC Fiber Connector: Compact for High-Density Deployments

LC fiber connector used in high-density networks — LC fiber connector with 1.25mm ferrule and latch mechanism.

The LC fiber connector features a 1.25mm ceramic ferrule and a latch-style locking mechanism. Designed for space-saving, it is ideal for SFP modules, fiber patch panels, and high-density rack systems. It's widely used for both single-mode and multimode fiber systems.

Ferrule size: 1.25mm
Mating: Push-latch mechanism
Typical Insertion Loss: ≤ 0.3dB

SC Fiber Connector: Reliable and Simple Push-Pull Interface

SC fiber connector with 2.5mm ferrule in a data communication system — SC connector used in telecom and enterprise applications.

The SC connector fiber type uses a 2.5mm ferrule with a push-pull coupling mechanism. Known for its reliability and ease of use, it's common in FTTH, PON, CATV systems. It’s compatible with both simplex and duplex configurations.

Ferrule size: 2.5mm
Mating: Push-pull mechanism
Insertion Loss: ≤ 0.5dB

ST Connector: Legacy Bayonet Style Still Found in Some Networks

ST connector with bayonet coupling for multimode fiber — ST connector often used in older LAN and educational networks.

The ST fiber connector features a bayonet-style twist-lock interface and a 2.5mm ferrule. Though largely replaced by LC and SC, ST connectors still appear in legacy multimode installations like universities and campus LANs.

Ferrule size: 2.5mm
Mating: Bayonet twist-lock
Use case: Legacy multimode networks

FC Connector: Precision and Ruggedness for Industrial Use

FC connector with threaded coupling for stable optical link — FC connector ideal for lab and vibration-prone environments.

The FC connector uses a screw-on threaded coupling, ensuring strong mechanical stability. It’s typically found in test equipment and high-vibration environments.

MTP/MPO Connectors: Multi-Fiber Solutions for Data Centers

MTP MPO connectors with 12 or 24 fibers for data center applications — MTP/MPO connectors streamline high-bandwidth deployments.

MPO (Multi-fiber Push On) and MTP (an enhanced version by US Conec) support 12, 24, or more fibers in a single connector. These are critical for 400G Ethernet, parallel optics, and ultra-high-density backbones.

Comparison Table: LC vs SC vs FC vs ST vs MTP vs MPO

Connector	Ferrule Size	Coupling Mechanism	Strengths	Typical Use
LC	1.25 mm	Latch	Compact, low loss	Data centers, SFP modules
SC	2.5 mm	Push-pull	Durable, low cost	FTTH, PON systems
FC	2.5 mm	Screw-on	Secure under vibration	Test equipment
ST	2.5 mm	Bayonet twist	Easy in legacy multimode	Legacy LANs
MPO/MTP	Multi-fiber	Push-pull	Ultra HD, bulk deployment	Data center backbone

Frequently Asked Questions

What is the difference between LC and SC connectors?: LC connectors are smaller (1.25mm ferrule) and better suited for high-density environments. SC uses a larger 2.5mm ferrule and is easier to handle but takes more space.
Are ST connectors still used today?: ST connectors are used in older multimode networks and educational institutions but are becoming obsolete.
Which connector is best for data centers?: LC and MTP connectors are most commonly used due to their compact size and multi-fiber capacity.

Conclusion

Each fiber connector—LC, SC, ST, FC, or MTP—serves a unique purpose. LC fiber connectors are best for dense environments, SC connectors for telecom reliability, and ST connectors for legacy compatibility. For ultra-high bandwidth, MTP/MPO is the clear choice. Choose wisely based on your system's current and future demands.

Releted Article:

OM1 OM2 OM3 OM4 OM5 Multimode Fiber Types: What is the Difference?