Upstream
USB channels 1-8 route directly from the stereo channels input connectors. It will either source from the Line or phono connecter depending on how the switches on the rear connector panel are configured. This is for the implementation of DVS.
USB Channels 9-10 route from the Aux send1 bus (post-fade). Channels 11-12 can either route from Aux send2 (post-fade) or the Master bus (pre-fade & insert). 11-12 are configured with the routing switch located on the top panel.
Downstream
USB channels 1-8 route directly to the source selector switch. Select USB 1 or 2 depending on what USB sound card you are connected to.
USB channels 9-12 route directly to the source selector switch of the two main return channels A&B.