An inspection control station is the portable or fixed control unit on the car roof, in the pit and in the machinery space that lets a technician move the lift at reduced speed while working in the shaft. EN 81-20 limits inspection speed to 0.63 metres per second and requires constant-pressure buttons, so the car stops the instant the button is released. Each station has its own stop switch, and when inspection is selected all normal and landing calls are disabled. Where several stations exist, priority rules prevent conflicting commands.