The digital inputs (i.e. S/PDIF or AES/EBU) can be routed to channels 1-2 or 9-10 of the ADAT Bridge. You must have Computer connector B hooked to a DSP card to access the second set of inputs/outputs. If you want to see all 16 inputs from your ADATs, you should have both group A and group B set for Ch 1-2 input ADAT. If you want to use Group A inputs from your ADAT and use the digital ports for digital effect sends/returns, Group A would be set for Ch 1-2 input = ADAT and Group B would be set for Ch 1-2 input = Digital. Similarly, if you want to record 10 channels of audio, but only have 1 ADAT, you can use the A/D converter of your DAT machine, routed through the ADAT Bridge I/O's digital ports, into Pro Tools on channels 9-10.