Sorry for the late reply. Your physical connection looks OK, all you should need is Tx and ground.There have been some issues with COM/USB adapters, so this is one potential area to look at. Other than that you need to confirm that the unit is actually sending data, and that the data is getting through to your virtual PC COM port - a simple serial data logger might help here, just to see if some data is getting through. There's quite a few of these around online if you search, but I don't have a specific one I can recommend. If you can't see data arriving in a simple serial logger, then the issue is somewhere upstream of your PC. If you do see data in the logger, then please post it here and we can investigate further.