AS-Interface for hazardous areas The decentralised AS-Interface I/O modules of the ClassicLine series with quick mounting technology connect binary and analogue sensors and actuators to the gateway or PLC via AS-Interface. The AS-i AirBox is a combination of an I/O module and a solenoid valve. In pneumatic applications, it is used for decentralised control of cylinders or valves, flaps and slides actuated by valve actuators. The dual inductive sensors with AS-Interface provide reliable feedback of the valve positions on pneumatic valve actuators and valves. In conjunction with an impact protection housing these units can be used in hazardous areas.