Direct Optical Mode

[alandbush]

According to my understanding, Direct Optical on the Phantom must be configured using Ethernet, as it must be set up using the speaker's IP address.

I am unsure as to whether the Ethernet is only required for initial configuration or whether I can carry on using it that way, or if I need to use Toslink after configuration.

Ethernet is ONLY required to select and subsequently configure Direct Optical mode.
Audio is expected ONLY on the optical input.

However, Devialet produce a product specifically for custom install and this speaker does accept analogue input. This is the model that you mentioned earlier.
I imagine they are only available from custom installers or more probably from Devialet direct.