A new type of USB cable is being demonstrated in Beijing, capable of delivering up to 100W of power over USB 2.0 or 3.0.  In the demonstration below, the Dell provides both video and power to the monitor when it is plugged in, when on battery it immediately shuts off the monitor.  Even better these cords are bidirectional and are able to sense which device requires power and which is the source of the power so you won't have to manually configure them.  The Inquirer does point out a major hurdle to overcome, if one singular USB cord able to recharge the battery of any laptop, many laptop makers will see that as taking away one of their revenue streams; their proprietary power bricks and expensive replacement parts.

"BEIJING: THE USB IMPLEMENTERS FORUM (USB-IF) is showing off a prototype USB cable system at the Technology Showcase at IDF Beijing that can deliver up to 100W of power."

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