... transmission among RS-232, RS-485 and RS-422 serial ports/ OverviewFM280 is a RS-232/RS-485/RS-422 ... transparent transmission among RS-232, RS-485 and RS-422 serial ports. It has anti-jamming function, surge protection function and lighting ... fiber cable, Features Zero delay automatic transmission; Adopt automatic monitoring serial signal rate, auto distinguish and control data transfer direction; ...