EtherCom EFM12N TX to FX Fast Ethernet media converter/ST fiber The EFM12N is a fully transparent device that does not have auto-negotiation abilities. Because of this, both units on each side of the EFM12N need to be configured the same way, either Full Duplex or Half Duplex (FDX or HDX). This configuration could be achieved via management software or manually, see the units user?s guides.
