This simple wiring system consists of four components: the AS-i Master, an AS-i power supply, the yellow AS-i cable, and the AS-i slaves. Using piercing technology, sensors and actuators are connected directly to the AS-i cable. The unshielded two-conductor cable carries both power and communication, including safety signals. As a result, AS-Interface eliminates cumbersome parallel wiring. The AS-i Master controls the data communication on the network. As a Gateway it creates the connection between the AS-i network and the controller (e.g. PLC). The upper-level fieldbus treats it like a fieldbus slave. Integrating an AS-i network into an existing fieldbus or Ethernet system is no more complicated than adding any other I/O module.