ATOP 400G QSFP-DD DR4 1310nm 500m Transceiver is designed for use in 400G Ethernet with a maximum transmission distance of 500m on OM4 multi-mode fiber (MMF). This 400G DR4 module enables a dense-port and high-throughput solution with its compact size and low power consumption. It can be used in various network applications, such as Internet protocol switches and routers. It is fully compliant with QSFP-DD MSA. Digital diagnostics functions are available via the I2C interface, as specified by the QSFP-DD MSA.