investigate are: Audio Interfaces- XLR , TRS , S/PDIF , TOSLINK , AES/EBU , ADAT , BNC , ETC… Channels / polyphony – Mono / Stereo , 16 channel digital, 5.1 & 7.1 ? Microphone Pre-Amp(s) and other in line effects Computer Interfaces – PCI / PCI-E , Firewire , USB