A small device that acts as a base station clips onto the top of the screen, continuously picking up the user's input with the Duo. According to Lee Jae-jun, head of research and development at KCI Communications: "The pen's co-ordinates are calculated by the amount of time it takes for the infrared and ultrasonic waves to be reflected from the base station."
The user can write or draw directly on the screen in eight different languages, marking up Web pages, documents or PowerPoint presentations, while using the pen to navigate through the desktop. The Duo also converts into a ballpoint pen. Notes written on paper appear in the included NoteTaker software. The Duo automatically synchronises with the Windows Vista and Windows 7 tablet software.
We suspect that there might be a couple of minor problems with the Duo. If you're using it with a laptop, it's highly probable that writing on and tapping the screen would cause it to sway, forcing the user to grab one side of the screen with their free hand. Another issue concerning laptop use is the possibility of the base station draining battery life, as it's powered via USB.
The Duo is available for about $120 (£75), making it possible to have just about the cheapest tablet PC yet. By November, the Duo will work with monitors measuring up to 22 inches diagonally, and will be available for Apple Macs as well.