This modular adapter has a DB25 female connector that plugs into DB25 RS232 serial port and converts it to an RJ45 connection.
RJ45 Pinout:
Pin1 -- Blue
Pin2 -- Orange
Pin3 -- Black
Pin4 -- Red
Pin5 -- Green
Pin6 -- Blue
Pin7 -- Brown
Pin8 -- White
* Gold plated pin
* 26AWG wire
* Molded ivory color housing
* Thumb screw