I would suggest double checking all of your Radio settings to be sure they are correct per the D-RATS suggested settings. What version of D-RATS are you running?
I use the RT Systems USB-RTS05 (orange cable) for all of my Icom radios. D-RATS works fine on all of them; ID-5100, ID-51a Plus, ID-880H and both of my IC-2820's. I have not found anything that I cannot do with this "proprietary" cable vs any other, either Icom or homebrew. The ID-51 DATA port outer diameter is smaller than standard, so make sure the cable end is all the way in. Homebrew cables may not fit, and need to have the outer housing trimmed slightly.
Note: The program only looks to see if the COM Port is connected, not the radio itself, so a bad connection at the radio will give you a No TX situation.
Jeff
VE7GIE
