The plug-type singlemode attenuators are used directly on the ends of fiber optic jumpers prior to installation in adapters. ST fiber optic attenuator is used with ST connections. Telecommunication Networks: Optimizes signal levels for stable and efficient optical transmission. are the female to male type, which is also. FTTMAX attenuator has high attenuation accuracy, reliable performance, low IL and high return loss, and is widely applied to test equipment, data center, CATV system etc. SC, FC, LC, ST, MU and E2000 type available.