FC Fiber Optic Patch Cord stands for Fixed Connection. It is fixed by way of a threaded barrel housing. FC connectors were designed for use in high-vibration environments. OM4, OS1, OS2 multi-mode and single mode variants, Both ends are terminated with a high performance hybrid or single type connector comprising of a SC. E2000 connector in simplex and duplex. These are typically not ruggedized, depending on the application and a spring loaded. Here is a plain-language breakdown of the four main connector types, the specs that actually matter, and how to match a cable to your equipment without guesswork.