This document provides specifications for the SFP-1G-BX80U-49/55-T02 1G bidirectional SFP transceiver module. The module operates at 1.25Gbps over a single mode fiber connection up to 80km using 1490nm lasers and 1550nm receivers. It has an operating temperature range of 0-70°C and includes digital diagnostic monitoring functions. Pinouts, optical and electrical characteristics are defined along with ordering information for the module.