Plug and Play (PnP) is a capability developed by Microsoft for its Windows 95 and later operating systems that gives users the ability to plug a device into a computer and have the computer recognize that the device is there. The user doesn't have to tell the computer. In many earlier computer systems, the user was required to explicitly tell the operating system when a new device had been added. Microsoft made Plug and Play a selling point for its Windows operating systems. A similar capability had long been built into Macintosh computers.
With Microsoft's participation, Plug and Play has been replaced by an open, industry standard, Universal Plug and Play (UPnP), which uses Internet protocols for seamless device plug-in.
Also see plug-in.