A compressed-air feed system for operating a pneumatic system includes a compressed-air supply, a compressed-air connection to the pneumatic system, a ventilation connection to surroundings, and a pneumatic main line between the compressed-air supply and the compressed-air connection. The pneumatic main line has an air dryer and a regeneration throttle. The compressed-air feed system further includes a ventilation line between the pneumatic main line and the ventilation connection. The ventilation line has a ventilation valve and a ventilation throttle. The compressed-air feed system further includes a bypass line between the compressed-air connection and the air dryer. The bypass line has a bypass valve formed as a 2/2 directional valve configured to permit an air flow conducted via the air dryer, and bypassing the regeneration throttle, for filling and ventilating the pneumatic system.