I ordered a bluetooth USB adapter, on the chance that it might work, and hooray! Doesn't work with vmlinux-4.1 but 4.8(.8) does the trick. I can send files from Ubuntu to my phone or tablet.
However, if it try to read my cell phone or tablet from Ubuntu, I get
No idea what "service settings" means, but not too important. I am able to send files from phone or tablet to Ubuntu, which is what I would normally do anyway, and I think I may have googled a fix for the failure to launch problem.Failed to launch default file browser
The specified location is not supported
You can enter an alternate browser in service settings
One of the devices I have paired with Ubuntu bluetooth is a bluetooth speaker. It gets listed as
Why "Microphone"? And why when I have it paired and play a music file in Ubuntu does the sound only come from my desktop speakers and not from my bluetooth speaker? Again, not a very important matter, because the desktop speakers are the sensible way to play audio from the desktop, but it is a puzzle. I really only want to use it with phone or tablet, where it works fine.BLKBOX POP360
One more puzzle. I keep getting one or two devices listed when I search that are complete mysteries. I thought devices have to be close to connect, but I live in a 5th floor apartment. Would something upstairs or downstairs be close enough?