Wi-Fi investigate

Cheat Sheet: Bluetooth

Device shall speak unto device...

Bluetooth? The name doesn't give much away, does it?

Not really. Bluetooth technology is named after a Danish King, Harald Blatand - which translates as Bluetooth - who ruled between 940 AD and 985 AD. Harald united Denmark and Norway by particularly bloody means and it is this ability to tie things together that compelled mobile phone company Ericsson to name the technology after him. Either that or he was a great communicator. Pick your myth.

So it's Ericsson's baby

Ericsson kicked off a study in 1994 to see whether a low power, cheap radio interface between mobile phones and their accessories could be developed. In 1998 the Bluetooth Special Interest Group - SIG - was formed with Ericsson, IBM, Intel, Nokia and Toshiba at its core. Bluetooth was now being developed in earnest.

So, what does it really do?

In theory Bluetooth facilitates a world without wires. It's a protocol that allows devices such as mobile phones, laptop computers, desktop PCs, keyboards and more to speak to each other within a range of 10m, or possibly even 100m in some cases. Unlike infra red it doesn't require line of sight to connect devices and is able to support several device connections simultaneously on a channel, making it handy for office use.

But aren't there enough wireless protocols floating around now?

You could say that. The biggest competition for Bluetooth is the 802.11 specification. The popular spec is 802.11b which runs on the same radio frequency as Bluetooth - 2.4Ghz. However, the uses of the two protocols are slightly different. Bluetooth is aimed at connecting little devices in and out of the office, whereas 802.11b is designed to create stationary broadband network bubbles, within which a user can run around with wireless devices.

The real threat comes from 802.11a. It runs on the 5Ghz frequency which is nowhere near as crowded as the 2.4Ghz spectrum. It's a top end, high performance protocol and can shift data at ultra-broadband rates of 54Mbps as opposed to 11Mbps for 802.11b and Bluetooth version 1.1's pathetic 721Kbps.

However, 802.11a is illegal in Europe at the moment as there is already a widely deployed wireless LAN protocol on the 5Ghz frequency in the market, HiperLAN II. Also, Bluetooth may kick arse a bit more in its next incarnation - version 1.2 - which is expected to be able to hit data transfer rates of up to 10Mbps.

Right. So I can walk into a shop today and buy Bluetooth stuff?

Yes, you can. Manufacturers have been sticking Bluetooth chips in many of their devices for about 18 months now.

Excellent - so I can connect up my mobile phone, headset, laptop and PC at work?

With great difficulty. At the moment, most manufacturers are creating private bundles of Bluetooth-interoperable products which aren't able to talk to any other manufacturers' products.

But I thought you said Bluetooth chips can talk to all other Bluetooth chips?

Good point. The chips can talk to each other as they're on the same radio frequency but the specific functions of each chip are down to the manufacturer, including certain profiles on top of the basic Bluetooth protocol.

That's not very useful, is it

Indeed. Especially as individual manufacturers create those profiles, so one maker's printer profile will not necessarily be able to connect to another manufacturer's printer profile.

But when I was gadget shopping at the weekend, I didn't notice any warnings about all this stuff.

Yes, that's something to keep an eye out for. Most of those cheeky manufacturers are omitting to declare on the box what other devices their products can be used with. A bit sneaky.

So why doesn't the Bluetooth Special Interest Group do something about it?

Well, there are rumours that SIG doesn't want to do anything about its associate manufacturers spilling the beans on what Bluetooth devices their products will connect to. The problem is, if all the manufacturers start telling people what their stuff will connect to, consumers might find the competition has a more diverse range of connectivity. The companies at the top of the SIG tree - Ericsson, IBM, Intel, Nokia and Toshiba - are in the same boat.

When will Bluetooth get to where it's supposed to be then?

There are those in the industry who reckon these messy issues should start to smarten up within the next 12 months but who can say when you'll be able to walk into a shop and buy any Bluetooth-enabled product and not have to think about what else it will connect to.

Tell us what you think by posting a Reader Comment or emailing editorial@silicon.com

**Essential Links**
From the silicon.com archive
Bluetooth - the conspiracy over interoperability
http://www.silicon.com/a51971
Wireless
networks for all won't be a bean feast
http://www.silicon.com/a51889
Intel demos son of Bluetooth
http://www.silicon.com/a51712
Intel on 802.11 - It's dodgy but we love it
http://www.silicon.com/a51665
Cheat sheet: Mobile and wireless security
http://www.silicon.com/a51322
HP launches Bluetooth mobile printer device
http://www.silicon.com/a50890
Bluetooth: Up close and personal wireless freedom?
http://www.silicon.com/a45911

External Links
http://www.ietf.org/proceedings/00jul/SLIDES/ipobt-agenda/sld004.htm
http://www.bluetooth.com/
http://bluetooth.weblogs.com/
http://www.ericsson.com/bluetooth/
http://www.nokia.com/bluetooth/
http://www.motorola.com/bluetooth/
http://www.key3media.com/bluetooth/
http://www.cs.utk.edu/~dasgupta/bluetooth/history.htm

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