Does GIGAPort DG have an ADAT input and does it support S/PDIF?

No. GIGAPort DG provides a single optical 8-channel ADAT compatible digital output, but there is no digital input. It cannot be used to record signals. Also, the output is only in 8-channel ADAT format, there is no 2-channel S/PDIF option. You can connect GIGAPort DG only to devices with an optical ADAT input.