This DB9 programming cable is a straight ribbon cable with a Male DB9 connector on one end and a Female DB9 connector on the other end. The male end is supposed to be plugged into COMM1 of the PLCs and the female end is to be plugged into the PC's RS232 serial port.

If your PC does not have built-in RS232 serial port but has USB ports, then you should purchase a USB-to-RS232 converter. Note that not all USB-to-RS232 converter works perfectly. There is a user discussion on this topic at the following forum page:

http://www.tri-plc.com/yabbse/index.php?board=2;action=display;threadid=409

We recommend the following brand from serialio.com: http://serialio.com/products/adaptors/usb_serial.php