This document provides specifications for a 10G 1559.79nm 40km DWDM SFP+ transceiver. It includes details on the product description, features, functional diagram, optical and electrical characteristics, pin definitions, digital diagnostic monitoring interface, and package dimensions. The transceiver is designed for 10 Gigabit Ethernet links up to 40km over single-mode fiber and supports a data rate of 9.95-11.3 Gbps with low power consumption under 1.2W. It provides digital diagnostics functions for real-time monitoring via a 2-wire interface.