Communication trouble occurred in a parking lot system of a certain airport. The ground line of the system was shared with the elevators and movable walks inside the tranfer passage near the parking lot. The cause of the trouble was thought to be the influence of inverter noise installed in the elevators and the movable walks.

Consequently GroundNite Ground Line Noise Filter was installed with the parking lot system. The noise was immediately reduced greatly and the former communication trouble has never occurred since then.