Nullmodem adapter

pinout

This adapter will enable you to use a normal serialcable as a nullmodem

25 pin D-SUB female connector  to the Computer

Female Male Shield Ground 1 1 Shield Ground Transmit Data 2 3 Receive Data Receive Data 3 2 Transmit Data Request to Send 4 5 Clear to Send Clear to Send 5 4 Request to Send Data Set Ready 6 20 Data Terminal Ready Data Terminal Ready 20 6 Data Set Ready Ground 7 7 Ground

25 pin D-SUB male connector  to the Serial cable

Source:www.pinouts.ru