Each FIP provides a single network interface for both multimode and single-mode FDDI networks, and provides the interface for connection to a Class A dual attachment station (DAS) with primary and secondary rings, or to a Class B single attachment station (SAS) with only a primary ring. A 6-pin mini-DIN connector on the multimode-multimode FIP (CX-FIP-MM) and the single-mode/single-mode FIP (CX-FIP-SS) provides the connection for an optical bypass switch. When the interface is shut down, the bypass switch allows the light signal to pass directly from the receive port to the transmit port on the bypass switch, completely bypassing the FIP transceivers. The bypass switch does not repeat the signal, and significant signal loss might occur when transmitting to stations at maximum distances.