The BD370 and BD390 are essentially the same with both featuring BD Live etc, with the main difference between the two being the BD390 includes 1GB of internal storage for BD Live, and 7.1 discrete analogoutput.
Whether connected to a current Denon receiver or other product, audio and video signals are sent via analog audio output and S-Video to the respective inputs on a connected device in order to view the GUI and hear the audio.
As for output devices, even analog tube-based televisions can display convincing 3D content from 2D films, although the system generates a fair amount of flicker as it struggles to overcome the low refresh rate and interlacing of the once-ubiquitous technology.