Allow the use of low cost flexible UTP instead of bulky RS-232. Screw together hoods with an RS-232 connection on one end and an RJ-45 telephone jack on the other end. This unit allows you to configure your own specific pin out. When trying to run a serial connection over a very long distance, it is better to use an Ethernet line to do so. It will cut down on signal loss and interference.This modular adapter has a DB9 male connector that plugs into DB9 RS232 serial port and converts it to an RJ45 connection.