This document provides information about the FT-901B-S-LC20 series 155Mbps Fast Ethernet SFP transceiver module. It is a single-mode transceiver that transmits at 1550nm and receives at 1310nm over a single fiber with an LC connector. It has a reach of 20km and complies with relevant telecommunications standards. The document includes details on its features, specifications, optical and electrical characteristics, and dimensions.