The DBPro Daughter board
Similar is design to the main board ZxR, just half the size and missing some hexagons. The main note we can determine here is that it has its own dedicated Sound Core3D which means any audio input can be processed independently.
The daughter board I/O
On the left we have the DBPro cable port which allows it to connect with the main board. Note that this doesn't need a dedicated PCIe slot as all its needs are catered for via the main board, all this requires is a spare PCI bracket in your case. On the rear I/O in order RCA L&R input, optical out and optical in.
The daughter laid bare
Removing her clothes we find a pair of JRC 2114 opamps, a Ti PCM4220 high performance ADC with a resolution of 24bits and sample rate of 216kHz which has various applications and in this case is used for high grade recording.