This document provides specifications for a 1G 1550nm 40km CWDM SFP transceiver module. The module uses a CWDM DFB laser transmitter operating at 1550nm and supports data rates up to 1.25Gbps over single mode fiber connections up to 40km. It has an operating temperature range of 0 to 70°C and complies with SFP MSA and SFF-8472 standards. Pin definitions, optical and electrical characteristics, and ordering information are provided.