SC vs. LC Fiber Connector You Should Know

Nowadays, the SC and LC fiber connectors are recognized as the most popular choices of connectors. Both rugged connectors have the same good performance and offer a moderate cost. As we all know, they can’t interchange with each other and differ in design and dimension. However, do you know which one best suit your project? Which one is more promising? Regarding this question, we want to dig a little deeper into the difference between the SC and LC fiber connectors.

The SC fiber connector

the SC is the acronym for Subscriber Connector, also known as a square connector, sometimes called the stick-click connector or the standard connector. Designed by JP Nippon Telegraph and Telephone, it was among the first connectors to enter the market after the advent of ceramic ferrules. The SC features a snap-in coupling mechanism, a square shape, and a spring-loaded 2.5mm ferrule. It was the first connector standardized in the telecommunications specification TIA-568-standard in 1991.

Owing to its initial high price, twice as expensive as an ST, the SC at first didn’t make a hit. Thanks to its increasing popularity in the market, its manufacturing cost decreased. Due to good performance and fast deployment, it was the best connector till the coming of the LC. It has been widely used in singlemode fiber optic cable, analog CATV, GPON, GBIC, EPON ONU’s, Fiber Media Converters, and datacoms and telecom applications, like point-to-point and PON.

Covered in the FOCIS 3 Fiber Optic Connector Intermateability Standard TIA-604-3, the SC remains the second-best choice of fiber connector for simplex applications, duplex applications, and polarization-maintaining applications.

The LC fiber connector

The LC refers to Lucent Connector, named after its designer Lucent Technologies. Designed to fulfill the want of a smaller, low-loss connector, It features a 1.25mm ferrule, half the size of SC. Therefore is also known as the “little connector.”

Due to its tiny footprint, faster and easier to operate, low insertion loss, overall reliability, and push/pull with a latch design, the LC gradually dominates both singlemode and multimode deployments. Yet its introduction was not booming, as Lucent Technologies charged high license fees. Today, the LC has been the most popular fiber connector and is widely used in high-density networks, such as datacoms, SFP and SFP+ transceivers, XFP transceivers, etc.

Covered in the FOCIS 10 Fiber Optic Connector Intermateability Standard TIA-604-10, three different types of LC connectors are available:

• Singlemode LC APC
• Singlemode LC UPC
• Multimode LC UPC

SC VS LC

While LC and SC offer nearly the same insertion loss and return loss, the main difference lies in their dimensions and design. The main draw of the LC is the half-the-size of SC.

Name	Mating Cycles	Ferrule diameter	Standard	Cost	Release year	Ease of use	Application Features
SC	1000	2.5 mm	TIA-604-3 (FOCIS-3)	Cheaper	1992	Easier	Datacom and telecom applications, such as GBICs, PON, etc.
LC	500	1.25 mm	TIA-604-10 (FOCIS-10)	Higher	2002	Less easy	High-packaging density, SFP+/ SFP28, QSFP+ or QSFP28, etc.

Dimensions:

The SC has a standard 2.5 mm ceramic ferrule, while the LC, which is developed to compete with the SC, has a 1.25 mm ceramic ferrule, half the size of the SC.

Design:

The LC features a push/pull motion with a latch, while the SC takes a snap-in coupling design.

Cost:

Generally, the SC is cheaper than the LC, but the cost gap between them will gradually narrow with the economy of scale.

Applications:

The SC is more suitable for applications that call for high precision signals and are more sensitive to return loss. Due to its relatively larger size, it is less ideal for high-density environments.

Due to its smaller footprint, the LC has massive popularity in high-density environments, such as data centers and telecom switching centers.

Ease of Use

However, due to its smaller size, the LC is more difficult to insert/take out when compared with the SC.

Repeatability

The table above shows that the SC has 1000 mating cycles, twice as many as LC.

History and Reputation

Appeared in 1991, the SC has a good record over thirty years. Released in 2002, the LC is much younger. Notwithstanding, it’s speedily catching up in its favor due to its small size.

Mating SC-LC using a hybrid adapter or cord

It’s easy to convert SC to LC and vice versa. The SC-LC and the LC-SC hybrid adapters/patch cords are to adapt. Also, you can use cassettes to hold multiple LC or SC links over an MTP cable.

Conclusion

To put it simply, the LC seems more likely to win the competition eventually, as the packaging density is increasingly vital for us. And the LC connector is ideally suitable for higher-end QSFP+ or QSFP28 and 40 GbE or 100 GbE networking. Also, nowadays, GBICs are difficult to buy, where SC is the standard.

Although standardization matters due to SFP+ and QSFP+, the SC would still be one of the best choices for years. For example, some people find the SC preferable for patch panels because the SC is much easier to swap the cables in the duplex boot than LC.