I have a problem with communicating with an Industrial type PLC from my desktop PC ( ASUS M4a77T motherbd, Phenom processor, I can provide more details if necessary ). The program on the PC gives no reason for failure to communicate apart from an error message asking one to check cabling,etc. Connecting to an older Dell Latitude with the same cable and everything works fine.
Can anyone suggest what might be causing the problem. I've checked device manager and set the same settings as the laptop, viz :- 9600,E,1. I have run winmsd and the port is there and looks OK. The BIOS settings are 3F8 and IRQ 4 which matches with what everything else is configured as.
I am not sure where else to look or what to try to debug the problem.