Maybe it's a bit of a nomenclature issue. MusicCast is their wireless system, and the name of their app on the phone.
Initially, I used the MusicCast app to control the receiver, but all it saw was the Optical input, but no further access. I renamed Optical 1 to Optical B2. So I used the Brennan mobile or UI interface via Wifi to control the B2. I am not sure if the access is via the receiver wifi, the B2, or the LAN, but the music is via optical connection. I had the DLNA turned on, but not the NAS.
Today I turned on the NAS also, and now it's a source showing up on the MusicCast app, listed as Server. I renamed it to Server - B2. When I choose it as the source, it shows a basic structure of the files and folder, and can pick songs, albums, playlists, etc. But very basic, and the album covers don't seem to be linked to the albums. I didn't know to try the Server source before, and the NAS was off.
I had hoped that by having the DLNA turned on, the MusicCast app would read the Optical source B2 and list the music. My iTouch via the USB had a pretty workable system on the older version of the receiver, the R-N602. But not on the newer R-N803
Going forward, most likely I will use the B2 mobile to pick music, playlists, etc, and the MusicCast app to control source and volume, etc.
If you'd like, I can send you some screenshots showing the different displays between the optical input vs the server input.
I hope this clears it up, and that my minimum understanding of this stuff is close to correct!
Cheers,
Ethan