Campagnolo EPS (Athena) Interface A tiny electronic component that performs an extremely important job. The interface transforms the analogue signals received from the controls into the digital signals transmitted to the EPS Power Unit. But that's not all it does. It is also used to set the initial configuration and adjust drivetrain settings during a race, as well as displaying battery level. A vital component for the electronic drivetrain, it may be installed on the handlebar mount or on the brake cables.