GIGALIGHT 200G QSFP56 FR4 optical transceiver module is used for medium distance interconnection between devices within data centers and is compliant with IEEE 802.3bs 200GBASE-FR4 Ethernet transport protocol and also compatible with InfiniBand HDR transport protocol. This product is the DML version of 200G QSFP56 FR4 with a built-in pair of 4-channel CWDM MUX and DEMUX with center wavelengths of 1271nm, 1291nm, 1311nm and 1331nm, respectively, using a pair of single-mode fibers for transmission at distances up to 2km (FEC needs to be enabled). Note: DML has lower power consumption and cost compared to EML.