There are 3 types of UPnP devices: Servers control point and renderers UPnP servers incorporate software that enables products like the NaimUniti / SuperUniti / UnitiQute or any other UPnP compatible player to access and play their audio over your network. A UPnP server might be a Naim HDX UnitiServe hard disk player or a PC or Mac home computer. Some network attached storage devices (NAS) also incorporate a UPnP server. A variety of third-party UPnP server applications are available that are compatible with both Windows and Mac OSX such as Twonky MediaServer. Other options include the likes of Logitech Transporter Asset Playback EyeConnect Allegro VortexBox. These can be downloaded from the internet. Note that Windows Media Player version 11 and above incorporates built-in UPnP support so you won't need a third-party server app. A UPnP renderer is a device that plays back media content provided by a media server. Think of it as a client. A UPnP renderer can (but doesnt have to) include a control point. Most UPnP-capable devices will include a renderer and control point. The control point will control playback of UPnP media renderers. So products like the NaimUniti NaimUniti 2 UnitiQute and SuperUniti can play back and control audio stored on a UPnP server such as the Naim HDX or UnitiServe.