Right, I'm not sure if the telemetry function works in 6.6, all the other gcs functions should of course work.
The weird characters is actually mavlink data, so there is communication only maybe not correct....
Can you make a screenshot of the communication widget, just before you actually connect?. So, in gcs, add communication link, then your comport and take a screenshot from that widget...
And the rx cable TO your computer seems te be working, but can you checkout the tx cable?, AQ will always dump some mavlink data but all the other functions require a working return channel, mavlink wants a message back with specifications.
Maybe the line from the computer TX to AQ rx is buggy...
Just some checks, maybe we find something