ADAM-4520-F_DESCRIPTION.html
Most industrial computer systems come with standard RS-232 serial ports. Though widely accepted, RS-232 has limited transmission speed, range, and networking capabilities. The RS-422 and RS-485 standards overcome these limitations by using differential voltage lines for data and control signals. The ADAM-4520/4522 converter lets you take advantage of RS-422 and RS-485 on systems originally equipped with RS-232. It transparently converts RS-232 signals into isolated RS-422 or RS-485 signals. You do not need to change your PC's hardware or your software. The ADAM-4520 lets you easily build an industrial grade, long distance communication system with standard PC hardware. It extends the communication distance by 4000 ft. (1200 m) or increases the maximum number of connected nodes by 32."
