This refers to how well different pieces of equipment can work together. Macs and PCs, for instance have some limited interop, but there are many Mac devices that can’t work on a PC, and vice versa. This is an important notion for systemsThis is a very generic term for any collection of components that, all together, can do something. Systems can be built from subsystems. Examples are your cell phone; your computer; the radio in your car; anything that seems like a "whole.", like the IoTThe Internet of Things. A broad term covering many different applications where "things" are interconnected through the internet., that involve many different pieces of equipment working together.