QSFPDD-400G-FR4 is an Eight-Channel electrical, FourChannel optical, Pluggable, Single Mode Fiber, QSFP-DD transceiver for 400 Gigabit Ethernet Applications. It converts eight host electrical data lanes in each direction at 53.125Gbps into four optical lanes at 106.25Gbps, and multiplex them into one single mode fiber for 425Gb/s optical transmission. Each electrical lane operates at 26.5625 GBd / 53.125 Gbps (PAM4 encoded) and conforms to the IEEE 400GAUI-8 interface with host KP FEC. It allows communication up to 2km over a duplex LC connector Single Mode optical fiber cable. These modules are designed to operate over single mode fiber systems using CWDM nominal wavelengths of 1271nm, 1291nm, 1311nm and 1331nm. The optical interface uses a conventional duplex LC SMF connector. This high performance transceiver module is intended for medium-range SMF data communication and interconnect applications.