Is my Surface RT sending digital audio files to my DAC?

[captain zero]

My Surface RT gets .wav files from my NAS. The USB is plugged in to a DAC, which drives the stereo.

If digital files are going to the DAC, how can the volume buttons on the Surface modify the data stream? How can the equalizer of the software (Media Monkey) re-write the data files going to the DAC?

 

[Philip Hamm]

My Surface RT gets .wav files from my NAS. The USB is plugged in to a DAC, which drives the stereo.

If digital files are going to the DAC, how can the volume buttons on the Surface modify the data stream? How can the equalizer of the software (Media Monkey) re-write the data files going to the DAC?

The only way this can work is that the driver for the DAC includes these functions, and the Surface incorporates your DAC as an audio device. That's actually how I would expect a Surface RT to work with an external DAC.