A Human-Machine Interface (HMI) is the tool that allows the operator of a lift station to see data output and change parameters on the control panel. Typically an HMI is mounted on the control panel and consists of a 6”-10” screen with push buttons for the user. They range from black-and-white displays with limited push button controls to color displays with many layers of touch screen menus. HMI can also be referred to as OIT (Operator-Interface Technology) and was originally called an MMI (Man-Machine Interface).