Discovering Bluetooth Basics

Discovering Bluetooth Basics
Let’s get the biggest question out of the way first: What the heck is up with
that name? Well, it’s got nothing to do with what happens when you chew
on your pen a bit too hard during a stressful meeting. Nor do blueberry pie,
blueberry toaster pastries, or any other blue food. Actually, Bluetooth (www.
bluetooth.com is the Web site for the industry group) is named after Harald
Blåtand (Bluetooth), King of Denmark from 940 to 981, who was responsible
for uniting Denmark and Norway. The idea here is that Bluetooth can unite
things that were previously un-unitable. (We’re a little rusty on our medieval
Scandinavian history, so if we’re wrong about that, blame our high school history
teachers — if you’re a Dane or Norwegian, feel free to e-mail us back
with the story here!)
The big cell phone (and other telecommunications equipment) manufacturer
Ericsson was the first company to promote the technology (back in the 1990s,
as we mention earlier), and other cell phone companies joined in with Ericsson
to come up with an industry de facto standard for the technology. The Institute
of Electrical and Electronics Engineers (IEEE) — the folks who created the 802.11
standards that we’ve been talking about throughout Wireless Home Networking
For Dummies— have since become involved with the technology under the
auspices of a committee named 802.15. The initial IEEE standard for PANs,
802.15.1, was adapted from the Bluetooth specification and is fully compatible
with Bluetooth 1.1, which is the third and current version of Bluetooth.
If you’re looking for a few facts and figures about Bluetooth, you’ve come to
the right chapter. Here are some of the most important things to remember
about Bluetooth:
Bluetooth operates in the 2.4 GHz frequency spectrum. It uses the same
general chunk of the airwaves as do 802.11b and 802.11g. (This means that
interference between the two technologies is indeed a possibility.)
The Bluetooth specification allows a maximum data connection speed
of 723 Kbps. Compare this with the 11 Mbps of 802.11b. Bluetooth is
much slower than wireless LAN technologies.
Bluetooth uses much lower power levels than do wireless LAN technologies
(802.11x). Thus, Bluetooth devices should have a much smaller
impact, power-wise, than an 802.11 device. This is a huge deal for some
of the small electronic devices that are being Bluetooth-enabled because
it means that Bluetooth will eat up a whole lot less battery life than will
802.11 systems.
Because Bluetooth uses a lower power level than does 802.11, it can’t
beam its radio waves as far as 802.11 does. Thus, the range of Bluetooth
is considerably less than that of a wireless LAN. Theoretically, you can
get up to 100 meters, but most Bluetooth systems use less than the maximum
allowable power ratings, and you’ll typically see ranges of 30 feet
or less with most Bluetooth gear — meaning that you’ll be able to reach
across the room (or into the next room) but not all the way across the
house.
Bluetooth uses a peer-to-peer networking model. This means that you
don’t have to connect devices back through a central network hub like
an access point (AP) — devices can connect directly to each other using
Bluetooth’s wireless link. The Bluetooth networking process is highly
automated; Bluetooth devices actively seek out other Bluetooth devices
to see whether they can connect and share information.
Bluetooth doesn’t require line of sight between any of the connected
devices.
Bluetooth can also connect multiple devices together in a point-tomultipoint
fashion. One master device (often a laptop computer or a PDA)
can connect with up to seven slave devices simultaneously in this manner.
(Slave devices are usually things such as keyboards, printers, and so on.)
The really big deal that you should take away from this list is the fact that
Bluetooth is designed to be a low-power (and low-priced!) technology for
portable and mobile devices. Bluetooth (do they call it Bleutooth in France?)
is not designed to replace a wireless LAN. It’s designed to be cheaply built
into devices to allow quick and easy connections.
Some of the PAN applications that Bluetooth has been designed to perform
include the following:
Cable replacement: Peripheral devices that use cables today —
keyboards, mice, cell phone headsets, and the like — can now (or will
soon, in the very near future) cut that cord and use Bluetooth links
instead.
Synchronization: Many people have important information (such as
address books, phone number lists, and calendars) on multiple devices
(such as a PC, PDA, and cell phone), and keeping this information synchronized
(up-to-date and identical on each device) can be a real pain in
the butt. Bluetooth (when combined with synchronization software)
allows these devices to wirelessly and automatically talk with each other
and keep up to date.
Simple file sharing: If you’ve ever been at a meeting with a group of
technology geeks (we go to these meetings all the time, but then, we’re
geeks ourselves), you might have noticed these folks pulling out their
Palm PDAs and doing all sorts of contortions with them. What they’re
doing is exchanging files (usually electronic business cards) via the
built-in infrared (IR) system found on Palms. This is an awkward system
because you need to have the Palms literally inches apart with the IR
sensors lined up. Bluetooth, because it uses radio waves, has a much
greater range, which doesn’t require that direct IR alignment . . . and is
much faster to boot.
Look for even more cool applications in the future. For example, Bluetooth
could be used to connect an electronic wallet (located on your PDA or cell
phone — the line between these devices is becoming blurred, so perhaps
your PDA/cell phone-combo device) to an electronic kiosk. For example, a
soda machine could be Bluetooth enabled, and if you wanted a soda, you
wouldn’t need to spend ten minutes trying to feed that last, raggedy dollar
bill in your wallet into the machine. You’d just press a button on your PDA/cell
phone, and it would send a buck from your electronic wallet to the machine
and dispense your soda. (Pat will have a root beer, thank you very much.)
Another common future application might be customized information for a
particular area. Ever go to one of those huge conferences held in places like
Las Vegas? The booth numbers tend to go from 0 to 20,000, and the convention
floor is about the size of 50 football fields — in other words, it’s a real
pain in the rear to find your way around. With Bluetooth, you can simply walk
by an info kiosk and have a floor map and exhibitor display downloaded to
your PDA. We’re hoping that this is in place next time that we go to the
Consumer Electronics Show; we hate being late for appointments because
we’re spending an hour searching for a booth.