Transponders are usually used in some applications that the link length is much longer than what the power budget defines or there is not a clear line of sight between the two end nodes. OEO means optical-to-electrical-to-optical. It is one type of transponders. OEO converts optical signal to electrical signal and then to optical signal again. It allows for add-drop functionality, in addition to simple optical reply or transponder. Fiberinthebox supply 1G, 2G and 4G OEO, 125M~4.25G OEO Converter, 125M~1.25G OEO Converter, such as SFP to SFP Optical-Electrical-Optical type media converter / repeater to meet your different requirement. 10G OEO is also available.