Things to do:
1. If the Ch0 LED remains OFF all the time, can you test your PC/Cable/RSLinx setup on another PLC?
2. When you do the AutoConfig, does the Ch0 Port LED flicker? If the setup has worked on another PLC, but not on this one, then maybe the Ch0 port is damaged.
3. Is the Ch0 LED port LED slowly flashing at about a 2-3 second rate. If so then the port has been configured for DH-485 and will not respond to DF1. If this is the case then you will have to try RSLinx's AIC+/PIC DH-485 driver.
We need to isolate the problem to either:
1. The RSLinx setup.
2. The SLC5/04 port setup.
3. A hardware problem in either your PC, the cable or the SLC.