SC Connectors Explained

Published: January 4, 2025

, Last updated: January 27, 2025

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SC Connectors, also known as standard, square, subscriber, or Sam Charlie Connectors, were developed by NTT (Nippon Telegraph and Telephone) under the name “Subscriber Connector”. These connectors are favored for their cost-effectiveness and push-pull mechanism, particularly in Passive Optical Networks (PONs), converters, and telecom applications, often using APC ferrules.

The SC Connector's development paralleled the introduction of PC (Physical Contact) ferrules, which provide low-loss connections without index matching gel. NTT's research in the late 1980s led to the standards for ferrule end face radius and spring force, ensuring optimal physical contact. The connector's interface standards are outlined in IEC 61754-4 and TIA-604-3 and end face geometry in IEC 61755-3-1.

Available in both single-mode and multi-mode configurations, the SC Connector features a square shape, a 2.5mm ferrule compatible with FC and ST via hybrid adapters, and a reliable push-pull latching mechanism. This design not only allows for quick connection and disconnection but also supports higher panel density compared to twist-and-screw connectors like ST, enhancing reliability and speed in data transmission.

Manufactured mostly from injection-molded plastic, SC Connectors are less expensive to produce than metal counterparts like FC and ST. They are available in simplex or duplex configurations and can be either PC or APC. The SC was specifically designed to improve upon ST Connectors, particularly in telecom and data communications, by addressing signal interruptions through a floating ferrule design, a feature that has influenced subsequent connector designs like LC, MPO, and VSFF.

SC Connectors Explained

Key Features of SC Connectors:

Durability for frequent use
Low insertion loss (<0.5 dB) for signal integrity
Stable connections with a push-pull mechanism
Broad compatibility across various equipment and applications

Although older, SC Connectors remain a standard in many global networks, particularly for polarization-maintaining applications. However, they are being phased out in favor of more space-efficient designs like LC in new installations due to their larger ferrule size. Despite this, SC Connectors are still widely used in PONs and outdoor applications due to their robustness.

The legacy of the SC Connector is evident in its influence on newer, smaller form factor connectors like LC and VSFF, which retain its design principles but with reduced size.

Assembly of the SC Connector is similar to other connectors, but requires specific equipment.

About the Author

Kathleen Skelton Kathleen Skelton, Director of Strategic Marketing, has worked in the fiber optic, cable and connector industries for over three decades. Her core competencies in fiber optics include technologies that enable the growth, integration and performance scalability of voice, data and video communications networks and services, having worked with a majority of the strategy managers in the industry during her tenure with Lightwave. Kathleen’s marketing expertise resides in business development, strategic and digital best practices and content management. Kathleen resides outside of Boston, MA with her family. Follow @KATHLEENSKELTON

Ron Schutjens Ron Schutjens joined the Fiber Optic Center, Inc. (FOC) technical team in 2023 with his extensive knowledge of the complete fiber optic assembly process and equipment in high-volume and high-variation environments. After graduating with a MSc. in applied physics, Ron started his career in fiber optics, after relocating to Florida. Having more of an affinity for hands-on engineering, he married his education with learning the processes and equipment and quickly moved up to a manufacturing engineer position at a cable assembly house. His experience includes Compulink, later Leviton, mainly serving the commercial telecommunication industry in fiber optics assemblies. During his time as manufacturing engineer, Ron has been part of many projects for product improvements and qualifications during the design and production scale up phases. At FOC, Ron offers his practical experience working directly on the production floor to service customers, embracing challenges, and offering process improvements.

About Fiber Optic Center, Inc.

Fiber Optic Center, Inc., (FOC), is an international leader in distributing fiber optic components, equipment and supplies and has been helping customers make the best cable assemblies in the world for over two decades. Several areas of specialization and expertise, in which they are the industry leader, make them the preferred choice for many of the world’s fiber professionals. In these key technology areas, FOC is "at least as technical as the manufacturer" about the products they sell. Striving to "make the business part easy," they offer outstanding and personal customer service, low or no minimum purchase order values, and from-stock delivery on industry-leading products and technology. FOC is the industry connection to the most innovative optical products, technologies and technical experts who integrate their manufacturing knowledge and vast experience into customers' worldwide operations. @FiberOpticCntr

For further information contact:

Fiber Optic Center, Inc., 23 Centre Street, New Bedford, MA 02740-6322
Toll Free in US: 800-IS-FIBER or 800-473-4237 . Direct 508-992-6464. Email: sales@focenter.com or fiberopticcenter@focenter.com

For media contact:

Kathleen Skelton, Director of Strategic Marketing, C: 617-803-3014 . E: kskelton@focenter.com

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