The Rundown on Bluetooth

The world is going wireless and I for one am happy with the change. After spending
twelve years figuring out the tangled tar balls some companies call network
closets and dealing with my own ever-growing array of peripheral devices, I
won't be sad to see the wires fall away from my computer connected devices.

Looking at the technology of wireless connections two main types are in the
lime light, which appear to be similar in nature, and in some cases it is hard
to tell which one should be used where. The one we hear about most often for
our home wireless networks is the Wi-Fi (IEEE 802.11b and g versions), but we
also hear a great deal about Bluetooth. While it is difficult to talk about
one without the other, we are going to focus on Bluetooth for this article,
and reference Wi-Fi for comparison when required.

The main difference between these two types of wireless connection is distance.
Wi-Fi (the IEEE 802.11b and g versions) can cover your entire house (even a
large 6 bed room depending on the antennas you use), while Bluetooth was designed
for 10 centimeters to 10 meters. Wi-Fi also focuses on computer-to-network connections,
while Bluetooth is designed to work with devices and peripherals to computer/network.

Bluetooth transmissions are weakened when attempting to go through steel, and
heavy concrete, and while Bluetooth devices can employ a transmission power
that produces a range in excess of 100 meters, most Bluetooth devices are designed
for use within 10 meters. Bluetooth focuses on high-speed over short distances
with low power requirements (to save on battery life).

In order to maintain the security of the data that you send over a Bluetooth
link, the Bluetooth standard includes several layers of security. First, the
two Bluetooth devices that are connecting use an authentication process to identify
each other. After the authentication process is complete (sometimes called 'pairing'
in techno-speak), the devices can begin sharing information.

The data sent across the radio link is encrypted (scrambled) so that only the
other authenticated devices have the key for decryption (unscrambling) of the
data.

Both Wi-Fi (the IEEE 802.11b and g versions) and Bluetooth use the 2.4 GHz
frequency radio band. There is quite a bit of confusion as to what terms such
as 2.4GHz and 900MHz really mean, thanks to the wonderful world of marketing.
A few years back there was a great deal of marketing for new wireless home phones
that ran on 2.4 GHz, rather than 900 GHz. The 2.4 GHz were said to run "faster"
and have a greater range. GHz, no matter what number is in front of it is a
bandwidth, just like radio bandwidth (such as what your car radio picks up).
You can listen to 91.5 or 105.3 on your FM dial, but neither is running "faster"
than the other, in fact the term "faster" really has no meaning at
all. The reason marketing was able to get away with this is that most home devices
ran on 900 Mgz (phones, microwaves, TV remotes, etc), so moving your phone to
the 2.4 GHz allowed connections with less interference from other devices. The
waves had less collisions (yep, that means exactly what you think it might,
waves running into each other).

To make full use of the 2.4 GHz frequency radio band and to reduce the likelihood
of interference, Bluetooth uses a transmission protocol that hops 1,600 times
per second between 79 discrete 1 MHz-wide channels from 2.402 GHz to 2.484 GHz.
Each piconet (small distance network) establishes its own random hopping pattern
so that you can have many piconets in the same vicinity without mutual interference.
If interference does occur, each piconet switches to a different channel and
tries again. Even though Wi-Fi (IEEE 802.11b/g) and Bluetooth both use the 2.4
GHz band, both protocols use hopping schemes that should result in little, if
any, mutual interference.

While Wi-Fi is moving to larger and large distances with higher transfer speeds,
Bluetooth is going for the devices ... and much like the USB port, the devices
are amazing in the breath they cover.

Wireles keyboards, mice, printers and cameras are all well known by now. How
about:

The Nokida Digital Pen -- As easy to use as a normal ink pen, the Nokia Digital
Pen provides you with an digital instrument that records as it writes. Slogan,
sketch, or signature - if it's written on digital paper, the Nokia Digital Pen
remembers it. Get a brilliant story idea during lunch? Jot it down and it's
stored in the pen. When you get back to the desk and put the pen in its stand,
your thoughts are transferred to your compatible PC in an instant. And since
it all works digitally, you can add colors and sketches to your notes for a
look that's even richer and more alive on screen than on paper.

http://www.nokia.com/

TomTom GO700 Navigation Device -- Unique Products, Mobile Phone Accessory Satellite
navigation system with full map of Europe & Bluetooth Dial Up Networking
and Handsfree in one. Also available in North America.

http://www.tomtom.com/

Seiko Wearable Pulse Sensor -- The wearable pulse sensor is a pulse meter designed
to be worn only around a wrist like a wristwatch; it automatically measures
the pulse, and is used together with a system for transmitting the measured
data to a medical center computer.

Bluetooth is a great technology for the creation of home and office devices
which can enhance our daily lives. That sounds like a really cool marketing
line, but its true. You can find out more about Bluetooth and the devices already
created for this wireless network protocol at :

http://bluetooth.com/Bluetooth/Connect/Products/