I have another thread going on this same issue but I'm taking another approach. I have two 750's I just had a new hard drive made and have machine one back on line but can't send a program in through the rs232 port Com 1 My other machine sends and receives fine as always. My setting are good it seems it dose not see the port. On my good machine the system con fig page has an icon windows com ports. When opened it lists Com 1 and Com 2 this icon is missing from the machine with the new drive. The guys who made the new drive say this should not have anything to do with my problem but I can't help but think this is the problem. I was hoping that those of you with 750's and 2100 controls who are using the rs232 could look at the sys con fig page for me and see if you have this icon (windows com ports ) If one of you dose not have this icon and are able to still communicate through the rs I would then know that the icon is not the trouble. Thanks for all the help so far, this is making me nuts and I need the machine badly.