AR0804 is an 8 XLR input, 4 XLR output AudioRack. Adding an AR0804 to your Qu system lets you position some of your I/O up to 120m from the Qu mixer, connected over a single Cat5 cable running Allen & Heath's dSNAKE protocol. dSNAKE provides control to the remote preamp, and all mic preamps are scene recallable. The AR0804 is simply an audio interface. It cannot be used by itself. It must connect to the Qu mixer which is where the audio is processed. Qu mixers are self-contained, so if you've already got the analogue cables you're good to go. If you're thinking of trading in the copper multicore for a Cat5 digital snake, Qu's dSNAKE port has you future-proofed, allowing connection to a combination of AR2412, AR84 or portable AB168 AudioRacks. dSNAKE is Allen & Heaths proprietary networking solution, boasting a transport latency of only 105us over cable runs of up to 120m / 390deg.. So if you're mixing FoH you can place your I/O on the stage and run a single Cat5 cable back to the Qu mixer in the mix position.