The AUX1 is a simple BUS access module that allows the
user to insert an additional mixer, mic pre, etc. into the Tonelux MIX
Each input is BALANCED and is calibrated for a level of +4 dBu
The LED at the bottom of the module indicates the mode that the AUX1 is
in. Internally, there are headers that allow you to switch the
jacks from the MX2 Stereo Mixer's busses to the MX5.1 Surround Mixer's
busses, since any combination of modules can be used at the same time
in the rack.
more info and technical specs.