No communication

[Guest Dark Dog]

I have a remote station with a radio modem and PLC SLC5/03. I changed an I/O card that went bad and crashed the system. I replaced it with the same type of card rewired for the same inputs in the same positions on the card reload the program. It works when I look through the laptop and DTAM interface. IT however, does communicate with my system here when I poll it. I checked the address and setup and it the same as before. Any idea on why it's not working? I can sure use the help. Also, when the station is polled I see the RX light flashing so I know it gets the poll, the Tx light just blinks once and nothing after. So I believe it's the PLC not responding. But why?