This is a media converter that converts a 10/100/1000base-tx(rj-45) to 1000base-sx(st) via a 850nm multi-mode fiber (MMF) ST connector, which allows distance reach up to 550M. This provides a cost effective conversion from 10/100/1000base-tx(rj-45) to 1000base-sx fiber, while extending the network reach beyond the 100M reach limitation of copper. The media converters are 100% Compliant for all of our networking needs. Now you have a cost effective solution to your network upgrade needs.