Thats correct. You shoul be have RS232 cable part no 1761-CBL-PM02. Connect your cable to your rs232 (PC to Plc with your cable).
Open your RSlinx. Setup your driver as RS232. This will make new driver for you as RS-232 DF1.
To make more easy for setup rslinx, just click the auto setup on your rslinx after choose driver. This action will auto detect your device (remember to install your cable befor do this cause rslinx will looking for defice and setting all for you).
After succed, you can open your RSlogix500 and selec who active.
Choose your micrologix and enjoy it, ok.
Times to beer....!