This Logilink product is a RS232 Serial RS485 Converter. It is a bi-directional converter which provides a reliable and efficient way to connect serial devices together using the serial RS-232 and RS-485 standards. It is equipped with an LED display for monitoring the functionality of the converter, an auto data flow control function, a hardware selector switch for communication interface selection, and a tera-Byte buffer size for reliable communication. The Logilink CQ3042S is compatible with all standard serial communication cables and ideal for applications such as industrial automation, PLC communication, ATMs, FAX and Modems, and many other applications where serial RS-232 and RS-485 communication is required.