No numerical volume display when using usb input

Hi, i am trying out the usb input into my bartok from an innuos streamer. When i have this connected via rj45 if i change the volume via roon then i see the numerical display, however this doesn’t happen via the usb input. Any idea as to why this should be?
Regards

When you use Roon, and stream via the RAAT protocol, it’s stack implemented within the dCS Mosaic firmware is able to directly control the dCS’ volume indicator.

Whereas a standard USB 2.0 driver, used when you connect to the dCS DAC via USB, does not include any such control mechanisms to manipulate DAC’s volume control indicator.

It’s not just with your Innuos, it’s the same even If you use a PC/Mac with Roon (connected over USB), or any other playback application.

Possibly of interest, Leo: