The adapter was first developed by NTT in Japan. FC is short for FERRULE CONNECTOR, indicating that its external strengthening mode is metal sleeve, fastening mode is turnbuckle. The earliest, FC type connectors used ceramic pins for the butt end. This kind of connector has the advantages of simple structure, convenient operation and easy fabrication. However, the optical fiber end is sensitive to fine dust and easy to generate Fresnel reflection, so it is difficult to improve the return loss performance. Later, this type of connector was improved by using a PC with a spherical butt end, but the external structure was not changed, which greatly improved the insertion loss and return loss performance.

The fibers are connected by an adapter through its internal open sleeve to ensure the highest connection performance between fiber jumpers. A variety of fine fixed flanges are also designed for fixing on various panels.

The conversion adapter can connect different types of fiber jumper interfaces and provides connections between APC end faces. Double or multiple connections can improve the installation density.