Square D Sy-Max PLC

We have a few old Square D Sy-Max PLC with a Mod. 500 processor. We have been using the SFW-375 software and a PC to communicate with the PC when we needed to. We use a NR&D SC902 programming cable to connect the pc to the plc and this has been working good for a year now.

Today we had the problem where we hooked up the PC to the PLC the same as always and when we go online with it we get the message:

UNABLE TO INITIALIZE ASYNCH

We tried using out spare cable but still get the same message each time. Does anyone have any suggestions of what we might try to get them communicating again.

When I check the utilities menu in the program here is the setup:
System Card: ASYNC
Com Port 1
Route: NONE
Baud Rate 9600

Any help will be greatly appreciated.

Thanks
Fred Johns

Just guessing here. Sounds like it might be a comm port problem on the computer. Check your CMOS BIOS setup to see if the port is enabled. If you have 2 comm ports on the computer try changing to COM 2 in the software and the cable. Even if you dont have 2 ports you might try setting the software to COM 2, reboot the computer, then change back to COM1, reboot again and try it. Hopefully your spare comm cable you switched to is ok also. Just some ideas, good luck.

Thanks, I will try that, both cables worked the last time we used them and I dont see any physical damage to them.