Bluetooth Wireless Networking
If your PC doesn't have
Bluetooth built in, a USB adapter is inexpensive and simple
buy a D-Link adapter. Their service is dreadful!
1 of a series on Bluetooth -
see also How to Choose a
The number of ways to
wirelessly connect an increasing number of formerly wired
devices is becoming confusing. Wi-Fi, 802.11a, 802.11b, 802.11g,
GPRS, IrDA and Bluetooth are just some of the terms now being
used to describe different types of wireless connectivity.
This article explains the
differences between the main types of wireless connectivity, and
explains how Bluetooth can be useful for you.
Different Types of Connectivity
To start off the discussion,
here is a table to show the major differences between the main
types of wireless connectivity and traditional networking.
115kb (- 4Mb)
Infra-red. The two devices must have their IR
ports facing each other. For simple data exchange.
Uses very little power.
refers to any of the three 802.11 types of wireless
service below, and to future new subcategories yet to be
released. Acts like a regular wired network in
most respects. Either built in or available as
add-on cards or adapters for desktop computers.
1 - 54Mb
commonly used, uses different frequency than 802.11b/g.
1 - 11Mb
common version at present.
1 - 54Mb
latest version, backwardly compatible with 802.11b.
120kb - 3Mb
devices (eg in most personal computing type devices)
have a short 30ft range, high powered Class 1 devices
have the longer range, and Class 2 are somewhere in
between. Either built in or
available as add-on cards.
rates possible with v1.2 (1 Mbit/sec) or V2.0 + EDR (3
suitable cellphone coverage
service used by GSM cellphones and by some add-on cards
for laptops and pda's. Speed typically about 30kb
depending on how many users are sharing the service on
each cell at any given time. A 2.5G service.
up to about 128kb
suitable cellphone coverage
compromise new types of 'always on' data service for
cell phones that are better than nothing but not nearly
as good as the 3G service that all cell phone companies
are hoping to introduce when funding and technology
varies widely, up to about 7Mb
suitable cellphone coverage
A current technology now becoming more
common in the US
which promises amazingly fast data transfer.
4G is under development with even faster speeds.
fashioned' way to dial up from a computer to the
'Broadband' connections to the internet.
Common type of cabled network in most offices (using
So What is Bluetooth?
Bluetooth is a very simple type
of wireless networking that can allow up to eight devices to be
connected together in a mini-network.
It is very short range in
operation, and so is considered to be for 'personal' networking.
With a range typically under 30ft, this allows enough distance to
perhaps communicate across your office, but not any further. This
short range is also its major security feature - anyone wishing to
eavesdrop on your Bluetooth communications would not only need
special equipment but would also need to be quite close to you.
It is a moderately slow type of
networking, but it can transfer data sufficiently fast enough for
most typical applications.
Bluetooth is hoped to be a very
low cost type of networking, and, as it becomes more widespread, the
cost of adding Bluetooth to devices should drop down to perhaps no
more than an extra $5-10 on the selling price.
Bluetooth is designed to be
compatible across a range of very different operating systems and
devices, including things that you would not normally think of as
being 'computer' type items - for example, some types of headset.
Bluetooth networking can enable the headset to connect with other
devices such as your phone, your MP3 player, your computer, or your
A Bluetooth enabled headset
would mean that you can leave your cellphone in your pocket or
briefcase, but still receive incoming phone calls. If your cellphone
supports voice recognition for dialing out, you can even place calls
as well as receive them, while never needing to reach for your
phone. The safety benefits of this, if you're driving, are obvious.
It is probably better from a
health point of view to have a very low powered headset close to
your head than it is to have a phone that might be generating 100 or
even 300 times as much radio energy close to your head.
Bluetooth can also help
different devices to communicate with each other. For example, you
might have a phone, a PDA, and a computer. If all three devices have
Bluetooth capabilities, then (with the appropriate software on each
device) you can probably share contact information between all three
devices quickly and conveniently. And you can look up a phone number
on your PDA (or laptop) and then place a call direct from the laptop
or PDA, without needing to touch your cellphone.
Bluetooth is not a magical
solution giving universal connectivity between devices. Each device
also needs to have the appropriate software as well as the basic
Bluetooth communication capability, and so sometimes the promise and
theory of what could be possible is not fully matched by the
For best compatibility, devices
should support the Bluetooth 1.1 standard. A new standard - 1.2, was
formalized in early November 2003 and this is now the
dominant standard. A newer
Bluetooth 2.0 standard, allowing for three to ten times faster
network speeds, and more careful use of battery power, is becoming
Bluetooth has been slow to
become accepted in the market, but now is starting to become
increasingly prevalent. Prices are falling and increasing numbers of
devices are offering Bluetooth connectivity. Over one million
Bluetooth devices are now being sold every week (although mainly
outside the US).
More information on Bluetooth
can be found on the
Bluetooth website. And here is a
useful site full of information on how to get Bluetooth devices
communicating with each other and your PC.
Bluetooth has three
different defined ranges, based on their output power ratings.
Class 1 devices are the most
powerful. These can have up to 100 mW of power, and a
regular antenna will give them a range of about 40 m - 100 m
(130 - 330 ft).
Class 2 devices are lower
power, with up to 2.5 mW of power. A regular antenna will
give them a range of about 15 m - 30 m (50 - 100 ft).
Class 3 devices use even
less power, with up to 1 mW of power. A regular antenna
will give them a range of about 5 m - 10 m (16 - 33 ft).
Most Bluetooth devices will
be Class 2 or Class 3.
Greatest range is not
necessary the best
Bluetooth has never been
intended for anything other than very short range communication.
With Bluetooth, short range
is actually a benefit for two reasons. Firstly, it reduces the chance of
interference between your Bluetooth devices and those belonging
to other people nearby. This is a very basic type of
Secondly, lower power means
longer battery life. Most Bluetooth applications get their
power from a battery, and anything that can be done to lengthen
the life of the battery is obviously important.
More powerful Bluetooth
devices can run into (and/or cause) problems due to swamping too
many other Bluetooth devices with their signals and exceeding
the eight device per network limit.
Devices that Use Bluetooth
A limited, but growing number of
devices use Bluetooth at present. Devices that are starting to have
Bluetooth connectivity built in include :
Digital cameras and camcorders
Keyboards and Mice
In-car handsfree kits
GPS navigation receivers
Home appliances (microwaves,
washers, driers, refrigerators)
In addition, add on Bluetooth
adapters are available for computers (eg with a USB interface) and
for PDAs (eg SD cards).
Bluetooth and the Internet
Bluetooth can be used to connect
between a device that has internet connectivity and another device
that does not, for example, you might use Bluetooth to connect from
your PDA to your laptop, and then your laptop might use Wi-Fi to
connect to a Wi-Fi router and from there you would be connected to
Sometimes when buying a PDA you
may find yourself with an apparent 'either//or' choice - either buy
a device with Bluetooth; or a device with Wi-Fi capability. In such
a case, it would seem at first glance that if you want to connect to
the internet - especially while traveling out of your office, Wi-Fi
would be a better choice.
However, this is not quite such
a clear choice. Wi-Fi 'hotspots' are few and far between. A much
better approach might be to get Bluetooth on your PDA and also on
your cellphone and use Bluetooth to connect to your cellphone and
then connect through your cellphone and out to the internet from
there. I use T-Mobile's GPRS service - they offer unlimited connect
time and unlimited bandwidth usage for only $20/month extra on top
of my regular cellphone service (and GPRS connection time does not
count against my monthly minutes - it truly is unlimited for only
In my opinion, this is the
perfect solution. GPRS coverage is much more widespread than Wi-Fi
coverage, and while it is not fast, it is adequate for simple mail
sending/receiving, instant messaging, and occasional web browsing
such as you're likely to do on a PDA. Although I also have Wi-Fi in
my laptop, these days I never use it, and indeed if I'm sitting in a
Starbucks with my laptop, I'll be connecting to the internet not
through the Wi-Fi in Starbucks, but via Bluetooth and my cellphone's
Which is better - Bluetooth or
Wi-Fi is primarily used as an
alternate to traditional cable based networks. It has a longer range
than Bluetooth, and supports faster data transfer speeds, and so it
might seem better than Bluetooth.
But, in reality, Bluetooth and
Wi-Fi have different purposes. Bluetooth is intended for limited
data transfer between many different types of devices, Wi-Fi is more
focussed on faster data transfer between computers on a network.
One of the distinctive elements
of Bluetooth is that is uses very much less power than Wi-Fi. Class
3 devices (such as are in PDAs, phones, headsets, etc) transmit a
very low power signal (1 mW) and only transmit intermittently when
in standby mode, saving even more power. Wi-Fi, on the other hand,
consumes a great deal of power, and so for any type of portable
battery operated device, Bluetooth will allow for substantially more
battery life than would Wi-Fi.
If you're simply wanting to swap
data between different devices in your office and elsewhere on a
casual and occasional basis, then - assuming that the software and
Bluetooth hardware is available - Bluetooth is probably a better
choice for you. If you need more range, and higher bandwidth;
perhaps if you want to connect computers into your office LAN, then
Wi-Fi is a better choice for you.
Bluejacking is a moderately
harmless 'fun' type trick that some people have discovered. It
involves sending messages from your Bluetooth device to other people
close to you with Bluetooth devices, and surprising the recipient in
The easiest way to Bluejack is
to create a new phonebook contact, with the message you want to send
in the name field. Then, in a busy place with lots of people (so
that there is a chance that someone might have a Bluetooth enabled
phone or PDA), choose the option to send your new contact via
Bluetooth. Your phone or PDA will then search for all Bluetooth
devices in range, and present you with a list. Choose whichever
device you wish from the list and send it. The recipient will get a
message asking if they wish to accept your contact, and showing the
text you entered as the contact's name (eg something like 'Bad
weather today isn't it' or whatever else you wish to say).
More details on Bluejacking can
be found on this
If you're planning to enjoy
Bluejacking (or Toothing, below) you'll probably want to get
your eye in to guessing how far away 10 m/33 ft is so as to know
how many people and devices might be within range.
Harmless Bluejacking didn't
take long to evolve into a more goal oriented social activity,
now known as 'toothing', whereby people communicate to other
Bluetooth equipped people around them, trying to arrange casual
and immediate trysts. Discussed in
this article and more information on
Bluetooth promises to be a low
cost, convenient, and simple way of enabling your various computer
devices to talk to each other and to their peripherals. The reality
has yet to match the promise, but Bluetooth is becoming more
widespread and functional every day. Bluetooth is almost certainly
in your future.
Bluetooth is not a competitor to
Wi-Fi. It offers different functionality for different purposes.
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20 Nov 2003, last update
21 Jul 2020
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