Wireless technologies inside and outside the office are now well and truly established, but cables still remain prevalent nonetheless. Take the computer monitor or a presentation display for example ? they are still tethered most of the time and while you cannot really pull away from the mains just yet, there are plenty of options around for streaming content from a device to an HDMI-enabled display.Google's Chromecast and Apple's AirPlay are both variants of Miracast, which is itself a take on Wi-Fi Direct, allowing two devices to easily set up an ad-hoc, temporary network to exchange data. Miracast dongles are relatively cheap ? you can get one for as little as a tenner but they do come with their own issues including compatibility and overall performance.