power/comms plug?

[djh]

OK, I've found the problem. The user that runs chromium needs to be a member of the dialout group in order to have access to ttyUSB0. I'm guessing the app was receiving a permissions error when it tried to open the device, so it would be helpful to report that.

BTW, the webstore now says I have version 8.3 and it looks like the picture in the webstore.

Now all I need to do is find out how to actually use the app to configure the device ...