When changing interfaces on a DSP Farm card, you must use the "Playback Engine" dialog (not the "Hardware" dialog) to select/remove the interface. This is to ensure that the session gets closed and reopened so that the proper I/O selections appear in the input/output pop-ups. Also, when a peripheral is enabled on a DSP Farm, 6 mixer channels on that Farm's first DSP chip must be allocated, leaving a maximum 30x2 mixer on that chip. This means that DSP might need to be rearranged on the card.