If the power unit is the brain of the Campagnolo EPS group, consider the Campagnolo EPS V2 Interface to be the voice. A simple LED light changes colors to communicate with the rider. Digital Tech Intelligence receives impulses from the controls and translates them to digital signals that are then sent to the power unit. The battery level can be checked by briefly pressing one of the two "Mode" buttons, and a designated color will reflect how much power the battery currently has. Campagnolo EPS V2 internal battery needs to be used with the new V2 DTI interface unit.