EB-120 is a media converter that can convert one RS-232 and/or one RS-422/485 ports to be transmitted over a single fiber or two fibers. A DIP switch is used to setup two-wire/ four-wire operation mode and to enable internal termination for RS-422/485 port, and to configure RS-232 port to operate in either DTE or DCE mode. EB-120 series are available in type of compact stand-alone box that can meet versatile field installation demands like on desktop and wall-mount.