Samsung claims that its UbiSync LCD monitor is the world's first USB-connected display, and needs no graphics card. The 19-inch 1280x1024 screen uses a software graphics adapter which it downloads to the PC when it is plugged into a USB 2.0 port.

Samsung senior vice president Ha Yoon-ho suggested that UbiSync would be ideal for laptop users wanting a second display, and for workers who need multiple PC screens. It includes a four-port USB hub, so up to five monitors can be connected via a single USB port on the PC.

UbiSync is due on sale in May for £349 - not cheap for a 19-inch monitor, but it does mean you can add an extra screen to a PC without having to open the box and install extra VGA or DVI ports.

The USB monitor uses British-developed video networking technology from DisplayLink. Its performance won't match a high-spec 3D graphics card but is fine for business use, said Michael Ledzion, DisplayLink's executive VP of world-wide sales.

He claimed that it is capable of 32-bit colour and DVD-quality video playback, even though it uses software on the PC and a video chip in the screen, instead of a graphics card in the PC.

DisplayLink has also licenced its technology to Toshiba, which has built it into a universal laptop docking station, and Ledzion showed a USB-DVI dongle from Taiwanese manufacturer Sunix which he said can add USB connectivity to any screen.

The same technology can be used to send video over wireless USB and Wi-Fi, Ledzion said.