You need to use the 1747-PIC module. This connects to your RS-232 port on your desktop and translates the comms to the DH-485 necessary to communicate with the 5/02. RSLogix supports this protocol but you have to go in and set up the PIC module as your choice of interface in the comms section of RSLogix. Once you do this, RSLinx will be configured to communicate to the processor through the PIC module.
Good luck with your adventures!