The BD-4321S-C2CDA from Shanghai Baudcom Communication Device is a Fiber Optic Transceiver with Data Rate 1.25 Gb/s, 2.5 Gb/s, Wavelength 1480 to 1500 nm (Tx), 1260 to 1360 nm (Rx), Distance/Reach 20 km, Output Power 3 to 7 dBm, Receiver Sensitivity -30 dBm. More details for BD-4321S-C2CDA can be seen below.