The ARC USB connects to your computer via USB, and talks to TotalMix FX directly.
It has 15 freely assignable and illuminated buttons, one encoder wheel, and a TS jack to connect a foot switch. The ARC USB is a USB 1.1 MIDI remote control for the Fireface UFX+. Thanks to operating as a UAC 1 class device, it is natively compatible to Windows and Mac OS X. As soon as it is present in the operating system, TotaIMix FX will automatically detect the ARC USB, and communicate with it via simple MIDI remote commands to control the UFX+ and all other RME products.