Charles Arthur: Look, no wires

Last week, British Telecom finally announced its wireless service for the world – so that joyful travellers at the Heathrow Hilton, and outside BT's headquarters in St Paul's, London and its Adastral Park research centre in rural Suffolk, can all hook into broadband-speed connections without wires, at least from the start of August. Deals are also being planned with the Bluewater shopping centre near Dartford in Kent, and Earl's Court Olympia in London. By the end of the year BT hopes to have 70 hotspots, and 200 by this time next year; by June 2005, it's aiming at around 4,000.

It's about time. The delay in offering these connections, which run at up to 11 megabits per second (the equivalent of an Ethernet network speed such as you'd find inside an office) has been caused by the somewhat fusty attitude of the Radiocommunications Agency, which had fretted that they would cause interference with other systems.

Despite a too-late (and, I suspect, misplaced) protest from the makers of systems such as remote car locks and burglar alarms, which use roughly the same 2.4 Ghz frequencies, the agency announced last month that it would give permission for commercial use of those frequencies – that is, companies could charge you for access.

If you're counting, you'll know that this makes at least two, and probably three, wireless systems that BT has pushed. But this one is for real, principally because it's not BT's idea.

But further out, there's more confusion coming. So hold tight as we take a quick tour of the wireless world, so you can work out what not to buy.

BT's wireless service will use the 802.11b standard (watch out for that "b": it'll be important). It's also known as "Wi-Fi". Pretty much every computer manufacturer and even PDA company has got an add-on for it. The amazing thing is that it took the Radiocommunications Agency so long to allow such an obvious moneymaking scheme, since charging for 802.11b access is a sure moneyspinner all over the US and in parts of Europe. An 802.11b plug-in card for a PC or notebook costs about £80, and lets you work without wires within a range of about 100 metres of a "base station". Think of it as tetherless broadband. It's data-only, but that's OK, because we all have mobiles for voice.

There's already another wireless system, based on Proxim's "HomeRF" protocol, which could be used for cordless phones as well as computing networks, voice and data. But as its name suggests, it was intended for the home, and these days you can't get any traction if you only sell to home users. HomeRF was too slow, and these days is pretty much dead in the water. So pitch that one overboard.

But things are about to get more confusing. Just when you were getting used to 802.11b (to me that rolls off the tongue more easily than "Wi-Fi", which just sounds horrible), two more 802.11 versions are coming along. It's like watching buses.

The first is already here: 802.11a offers data links of 54 Mbps, nearly five times faster than 11b. It also operates at a different frequency, of 5 Ghz. The speed makes it ideal for moving really big files around, and even gets close to what you need for shifting video. That has interested companies that want to produce "home media servers" to move video around the house: you pipe it in one place (your broadband connection or your TV aerial) and it can be passed to smart devices in the house.

Proxim, owned by Intel, has introduced its own 802.11a version in Europe – but it's a non-standard. It runs at twice the speed of the international standard, at up to 100 Mbps, but won't interconnect with other makers' 802.11a systems.

If that were all there was to it, Proxim would look smart: first mover in a rapidly growing market. But that difference in frequency between 802.11a and 802.11b (and don't ask me why "b" came before "a") is an important one. It means your 11b gear won't talk to 11a gear.

In fact, it would be wiser not to buy 11a gear at all – because computer companies are developing systems that use yet another standard, 802.11g. That runs at up to 54 Mbps, but crucially at the same frequency as 11b – meaning that your old 11b cards can talk to an 11g system. Your 11g products, meanwhile, talk to each other at 54 Mbps.

Phew. The only thing that 11a has going for it on this basis is that it's sort of here now, while 11g might get shown off, but not necessarily released, by companies like Apple Computer (which was first with 11b) later this year.

For companies considering a consumer market that is essentially flat-lining, and that hasn't been helped by all the revelations about companies such as WorldCom, there's no rush to put 802.11a into systems. And 802.11b is already here, and it works wonderfully well. So the sensible option if you want wireless now is to buy 11b; and if you want it later, hang on for 11g so your earlier investment isn't wasted. Because nothing is more annoying than obsolescence that you bring upon yourself – although obsolescence imposed by companies trying to get a marketing edge comes a close second.

network@independent.co.uk