Adam 4520 is an isolated converter for systems originally equipped with rs 232 it transparently converts rs 232 signals into isolated rs 422 or rs 485 signals you dont need to change your pcs hardware or your software the adam 4520 lets you easily build an industrial grade long distance communication system with standard pc hardware the adam 4520s opto isolators provide 3000 vdc isolation to protect the host computer from ground loops and destructive voltage spikes on the rs 485 data lin