4520 ADAM RS-232 to RS-422/485 Isolated Converter

ADAM 4520 :

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.

The RS-485 standard supports half-duplex communication. This means that just two wires are needed to both transmit and receive data. Handshaking signals (such as RTS, Request To Send) are normally used to control the direction of the data flow. A special I/O circuit in the ADAM-4510/4510S and ADAM-4520/4522 automatically senses the
direction of the data flow and switches the transmission direction. No handshaking signals are necessary—you can build an RS-485 network with just two wires. This RS-485 control is completely transparent to the user. Software written for half-duplex RS-232 works without modification.

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