Abstract: In order to facilitate the user’s access network’s upgrades and protect the original copper cable investment,a multimode Fast Ethernet Optical ＆ electronic media converter with enough bandwidth,stable performance,high reliability and low price is designed in this article.It mainly consists of electrical interface module of RJ45,Optical ＆ electronic media converting chip AL210 and integrated light-transceiving module of HFBR-5105.This paper first introduces the working principle of the transceiver,Optical ＆ electronic media converting chip AL210,and integrated light-transceiving module of HFBR-5105,and then gives detailed description of the design method,with specific schematic diagram.