This module is an attenuator with 3 modes.  An attenuator is like a volume knob – you can turn down the volume or strength of a signal using this module.

The first mode is linear – the input is attenuated by the knob and then sent to the output.

To select other modes, tap the button below the knob.  The selected mode is highlighted by a light.

The button at the bottom indicates the number of stages for the exponential and logarithmic modes (does not affect linear mode).  There are a maximum of 3 stages.  When you add more stages, the curve of the attenuator becomes more pronounced.