Connecting an old serial device through an adaptor is always a challenge. First, did you get the correct driver for the serial2USB installed at the Windows system and started that in 32 bit compatible mode (I recall there are no working 64 bit nativer drivers)? I did not recognize that there even is a working one. The last prolific version I tried on my Win7Pro machine did not work either and I never got my G196 updated. If you have the driver installed - and checked that it runs without correct signing, have your ever got anything through the data line, viewed by Terminal? If the driver is installed, and works, and you assigned a working COM to it (not all work with Garmins Plugin), does it say anything on the G196 confirming contact?