ST

ST (Straight Tip) is a standard type of fiber optical connector termination. It's a fiber-optic cable connector that uses a bayonet plug and socket.

ST connector uses a half-twist bayonet type of lock to keep the connection secure. It uses a 2.5mm ferrule with a round plastic or metal body. The connector stays in place with a "twist-on/twist-off" bayonet-style mechanism. And because STs are spring-loaded, you have to make sure they are seated properly.

Available in singlemode and multimode, ST connector features reliable and durable field installation, with a design that enables installers to crimp the back of the body directly onto the cable jacket.

Originally developed by AT&T, ST was the first de facto standard connector for most commercial wiring. It was one of the first connector types widely implemented in fiber optic networking applications, and is probably still the most popular connector for multi-mode networks, like most buildings and campuses.

Although extremely popular for many years, ST connector is slowly being supplanted by smaller, denser connections in many installations.