The Atmosphere A-RCA is a remote RCA/3.5mm audio input to an Atmosphere AZM audio processor. This expansion acts identically to the on-board RCA inputs. The AZM will automatically detect the A-RCA and dynamically assign appropriate audio settings, such as makeup gain, EQ, and auto gain control, to that input. The stereo inputs are summed to a mono signal before being sent to the AZM.