Stereo Phantoms without Dialog possible?

[ogs]

You can actually get stereo sound out of two Phantoms without a Dialog... but a Dialog is still required at  some point.

Here's how you can do it:
1. connect a source to one of the Phantoms via an optical cable
2. setup everything with Ethernet cables (this is where you will need the Dialog)
3. listen to your optical source (set the Phantoms' volume now)
4. unplug the Dialog

The Phantoms will continue playing fine and will "wake up" when the optical cable sends a signal.
You will not be able to control the volume as Spark won't work after unplugging the Dialogue (I do not know if the remote might help with this, I do not own one).

Which networking is necessary between the Phantoms for this to work? Is PLC good enough for 24/192 or is ethernet required? (I am trying to avoid wifi) Are you saying that the L R channel splitting takes place in the Phantom where optical is connected? Not in Dialog?
Sorry for all the questions!