In your RSLinx do the following:
1. no setting need in your PLC
2. just use a cross cable to connect between your PLC and PC
3. goto Communication>Configure Drivers
4. select RS-232 DF1 devices and click Add New... button
5. select the right Comm. Port for your PC
6. click the Auto-Configure button
7. if very thing is fine you should see the Successful message and your PLC will appear on the RSLinx