SC
Fiber Connectors · 8 specs
Direct Answer
The SC connector (Subscriber Connector / Standard Connector, TIA-604-3 / FOCIS-3) is a push-pull optical fiber connector developed by NTT. Utilizing a 2.5 mm ceramic ferrule and a square molded plastic body, it is a primary standard in telecommunications and FTTH GPON/EPON installations.
Source: TIA-604-3-B (FOCIS-3) / IEC 61754-4 · Last reviewed Aug 28, 2026
Specs
| Standard / FOCIS | TIA-604-3-B (FOCIS-3) / IEC 61754-4 |
| Ferrule Diameter | 2.5 mm |
| Ferrule Material | Zirconia ceramic |
| Latching Mechanism | Push-pull snap-in rectangular housing |
| Fiber Modes Supported | Single-Mode (OS2) and Multi-Mode (OM1–OM4) |
| Typical Insertion Loss | 0.20–0.30 dB |
| Polish Types Available | UPC (Blue), APC (Green–standard for FTTH PON) |
| Standard Duplex Pitch | 12.7 mm |
Design and Telecommunications Deployment
Engineered by Nippon Telegraph and Telephone (NTT) in the mid-1980s, the SC connector replaced twist-on ST connectors. Its molded square body enables audible snap-in locking and prevents rotational damage to the fiber core during mating.
GPON and FTTH Standard
SC/APC (Green) is the global standard for Gigabit Passive Optical Networks (GPON/EPON) in Fiber-to-the-Home (FTTH) subscriber drops. The 8-degree angled polish prevents optical return reflections from destabilizing high-power optical line terminal (OLT) laser transmitters.