Here’s an interesting development. A company called [DisplayLink](http://www.displaylink.com) has come up with a technique to send video over a USB link, rather than the conventional VGA or DVI. It doesn’t require an extra graphics card – it’s all done in the device driver.
Samsung’s SyncMaster 940UX 19″ LCD is the first monitor to use the technology, although competitors are sure to be hot on their heels. A couple of good reviews of the 940UX can be found [here](http://www.thinkcomputers.org/index.php?x=reviews&id=639&page=1) and [here](http://www.everythingusb.com/samsung_syncmaster_940ux_11970.html).
The video quality over USB is not quite as good as DVI, but it’s apparently a lot better than you might expect. It’d be fine for office apps, web browsing, etc, while you could still run full-screen video on your conventional DVI monitor.
A lot of people around the net are shrugging their shoulders and saying “so what?”. Just add another graphics card to your PC and you don’t need the fancy/expensive monitor, plus you’d get better performance.
I think they’re missing the point. This isn’t for the knowledgeable desktop user. It’s a simple way to add a second monitor to an office PC without needing to open it up. It’s an easy option to add a second external display to a laptop. It’s a way to add a second monitor to small-footprint PCs that don’t have room for another graphics card.
The DisplayLink site has more information that promises some very interesting future products. Using the same techniques as the USB interface, they can send video over ethernet, WiFi, and wireless USB. FireWire wouldn’t be hard, if they found a need. A really interesting product idea is their USB-to-DVI dongle – you wouldn’t need a monitor that supports DisplayLink, as the dongle would convert the USB signal to standard DVI for display on the monitor.
A wireless version of this would be fantastic for conference room projectors. You’d just plunk your laptop on the desk and display stuff on the projector without any messing about with cables.
I’d love a dongle that could convert from wireless USB or WiFi (or even ethernet) to a standard TV signal. Then I could output video from my laptop on the lounge to the TV across the room without having to drag a cable across the floor. Nirvana!
The DisplayLink USB interface currently supports Windows XP and Vista – no word yet on an OS X driver, so Apple users will have to wait to see what develops. This does now look like the most likely way I’ll get to run a second external monitor from my MacBook, though.