There are different types of I/O controllers. In general terms the I/O creates an interface between an Input and an Output device or connects to a computer interface and hardware asset. In the world of manufacturing these, I/Os can be used to connect to legacy machines – machines that do not have a computer interface and extract machine data from the machine signals. Signals are enablers for facilitating communication between humans and devices. Signals contain information such as data that can be converted to metrics for instance.