Optical Transceiver 20KM 32CH Video, No CH Backward Data RS485 Data 3 Levels Lightning Proof, Dual Power Input, 32CH Video Digital Video Optical Transceiver 19" 2U ... power supply;3, OEM accepted if you need special design;4, Transmission distance selectable: 2KM / 20KM / 40KM / 80KM/ 100KM. Default ... -directional transmission.6, RS232, RS485,RS422, etc Supportable Digital Video Optical Transceiver