For most of these mundane tasks bandwidth is not an issue either, though Alereon showed a notebook extending its display through a WUSB link. If you click on picture above  to enlarge it you can just see Alereon's WUSB card sticking out of the notebook's PC Card slot. In front of the monitor to the left is a Displaylink USB video adapter and a four-port WUSB hub with the lid off. The box with an aerial to the right of them combines the two into a single prototype wireless display extender. Just in front of that is a prototype Samsung WUSB camera docking station.

Pictured right are Alereon WUSB adapters in CF Card, Mini PCI, USB dongle, Express Card and PC Card formats. But for mobile devices like cameras and smartphones to exchange long files, WUSB will have to be very frugal indeed in its use of power.

Consumption issues are complex because WUSB tends to be used in bursts – it is not good, at least at this stage, at multimedia streaming. If it sends a movie it will either dump the whole thing over at once, or in large dollops, depending on the cache available in the target device.

Philips spin-off NXP yesterday announced a new Certified WUSB chip, the ISP 3582, which uses less than 10 microwatts in sleep mode and 600 milliwatts transmit power (oddly, slightly more power is used to receive files). Clearly a lot depends on how long it spends sleeping.

Optimising this is part of the aim of Version 1.1 development, and the thrust is to put the onus of power management on the host machine, in which consumption is less likely to be an issue. (Confusingly, the WUSB people use the word 'device' to mean anything linked to the host, as if that is itself not a device. Perhaps they think the more sensible word client smacks too much of client-server set-ups).

Version 1.1 will enable the host and client to establish time slots when they can communicate if necessary, so they do not have to be handshaking all the time.

Its adoption of Near Field Communication to pair devices follows the example of the Bluetooth Special Interest Group. This is also adopting ultrawideband (UWB) links, which underlie WUSB, for fast transfers; as I wrote earlier this year, the idea is to use Bluetooth for device discovery and signalling, and call up UWB when a fat data pipe is needed.

For many mobile applications this will put it into competition with WUSB. Jason Ellis, business-development director of Staccato Communications, which like many companies in this field develops products for both technologies, says that as things stand Bluetooth with UWB would probably be more efficient than WUSB. But this might change as the standard is tweaked and the chips are more highly miniaturised.

David Brenner, business-development director of communications software specialist Stonestreet One, said Bluetooth was low-cost and it would be relatively simple to support both technologies on one device. "Some product lines are already strongly associated with Bluetooth and they are likely to continue to use it."

Replacing wires with wireless links is not always straightforward. An obvious use for WUSB is to get rid of the connecting wires in 5.1 and 7.1 speaker systems. David Sroka, NXP strategic marketing manager, said he knew companies that were developing ways to do this but they have get round the problem of wireless latency. "They have to get the timing right to ensure that the sound reaches each speaker at the right time.