Bluetooth

Choosing A Bluetooth Headset

Creating a good wireless headset for Bluetooth is
actually difficult to do. The regular wired headsets
are easy to design – with ranging styles.

Bluetooth headsets can never be as small or as light
as wired headsets, simply because it needs to include
the battery and extra functions. This extra size
will impact how the headset mounts on or around
your ears.

Comfort
There seems to be two main styles of headsets for
Bluetooth. Some are held into place with a loop
around the ear. These styles are normally more
comfortable, although they may be less secure. The
others are held in place by being jammed into
your ear – and usually prove to be less comfortable.

Factors to consider

Cost
The cost is an obvious issue, something that you
really need to think about.

Ergonomics
1. Check to see if the device is easy to
quickly and conveniently put on your ear then take
it off again.
2. Are the control buttons on the headset
easy to use?
3. The headset should be comfortable to
wear for long phone calls.
4. Can you use it with a pair of glasses?
5. Check to see if you can wear it with
either ear.
6. When you aren’t wearing it, you’ll
need to se how you would carry it with you.
7. The weight is important as well, as you
don’t want something that has the risk of falling
off.

Ease of use.
1. The commands and controls should be
easy to remember.
2. The volume level should be easy to
adjust.
3. The unit should turn on quickly.
4. The manual should be very well written
and easy for you to understand.
5. There should be a support number for
you to call if you should experience any types of
problems.

Features
1. You’ll need to know about the battery,
the talk time, type, and how to tell when it is
going dead or fully charged.
2. How many devices can the unit be paired
with?
3. Compatability is also important, as
well as the warranty period.
4. Check the sound quality for both
sending and receiving audio.
5. What type of range does the headset offer
you?

Other important capabilities include voice tags,
last number redial, tranfer calls, 3 way calling,
link to other phones, call reject, and mute. You’ll
also want to note if it looks attractive, and if
it’s too big or too small.

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Bluetooth Wireless Networking

Bluetooth technology offers three different types
of defined ranges, based on output ranges. Class
1 devices are the most powerful, as they can have
up to 100 mW of power, with a regular antenna
giving them a range of around 130 – 330 feet.

The class 2 devices are lower power, offering up
to 2.5 mW of power. A regular antenna will give
them a range of around 50 – 100 feet. Class 3
devices use even less power, up to 1 mW of power
to be exact. With a regular antenna, they will
have a range of around 16 – 33 feet.

Even though you may not realize it, Bluetooth
wireless technology has never been intended for
anything other than short distance types of
communication. With Bluetooth wireless, the short
range is actually a benefit.

For one, the short range will reduce the change of
interference between your devices and those that
belong to others who are nearby. Overall, this
is a basic type of security, designed to protect
you and your devices.

Secondly, the lower power used for short range
means a longer battery life. Most Bluetooth
devices will get their power from a battery,
meaning that anything you can do to lengthen the
battery life is very important.

The wireless networking offered by Bluetooth is
actually among the best, even though it uses
short range communication. Bluetooth is used
with wireless controllers, the internet, and
even wireless headsets.

For the best in short range technology, Bluetooth
is extremely hard to beat. If you’ve never tried
Bluetooth before, now is the time. It’s the best
with wireless networking, especially for those
who enjoy hands free talking on their cell phone.

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Bluetooth Versions

Version 1.1 and earlier
Since the technology of Bluetooth was introduced in
1998, several specification versions have been
released. Versions 1.0 and 1.0B had too many issues
and problems for manufacturers to develop devices
for Bluetooth. The main issue was the lack of
communication among the devices.

The core specification version 1.1 is the first
successful operating version of Bluetooth. Version
1.1 corrected a majority of the bugs and problems
found in earlier versions.

Version 1.2
Many of the newer Bluetooth devices, such as the
newer cell phones are being sold with the newer
Bluetooth version 1.2. This version offers backward
compatability with Bluetooth 1.1, faster transmission
speeds, received signal strength, and a host
controller interface (HCI) support for 3 wire UART.

Bluetooth version 2.0
It’s true that there may be multiple communication
technologies, although they all share one common
trait – faster is better. Bluetooth specialists
realized this, and therefore worked on improving
the speeds of version 1.2. The newest version,
version 2.0 + EDR (Enhanced Data Rate) was
accounced in 2004 and became available in late
2005.

Version 2.0 delivers data transfer rates of up
to three times that of the original version of
Bluetooth. Version 2.0 also provides enhanced
connectivity. With Bluetooth 2.0 + EDR, you’ll
be able to run more devices at the same time -
with more efficiency.

Computers and even computer related devices are
expected to be some of the first devices to
encorporate Bluetooth 2.0 + EDR, followed of
course by audio and imaging devices.

Version 2.0 is backward compatible with previous
versions, three times faster, and offers an
enhanced data rate of 2.1 MB a second. It also
offers broadcast and multicast support, along
with a further enhanced bit error rate
performance, making it the best Bluetooth has
ever seen.

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Bluetooth Technology Intro

The technology of Bluetooth is nothing new, but in
many respects it can still seem like more of a buzz
word rather than an accepted technology. You may
see the ads for Bluetooth enabled devices, although
you still may be wondering what it is.

Capabilities
The Bluetooth definition is a wireless technology
that is a worldwide specification for a small form
factor, low cost solution that will provide link
between mobile devices and other electronic
devices.

Similiar to 802.11 b/g wireless and many cordless
telephone systems, Bluetooth operates on 2.4 GHz
radio signals. The 2.4 GHz band seems to be a bit
crowded, with interferences between the devices a
bit hard to avoid. Telephones are now being offered
at the 5.8 GHz frequency band, which will help to
remedy this.

The technical specifications of Bluetooth will
indicate a maximum transfer rate of 723 kbps with
a range of 65 – 328 feet, all depending on the
class of that particular device. The speed is a
fraction of what is offered by wireless standards,
so it’s obvious that Bluetooth doesn’t really
pose a threat to replacing your wireless network.

Applications
There are numerous products that will take advantage
of Bluetooth capabilities, such as laptops, PDAs,
headphones, and even wireless printer adapters.

A lot of laptops out there will include an onboard
Bluetooth adapter which allows the system to
connect to any Bluetooth device right out of the
box. For computers that don’t have an adaptor
built right in, there are several USB adaptors
available for Bluetooth.

For an awesome technology, Bluetooth is actually
hard to compete with. For short range wireless,
Bluetooth is easily one of the best. The standard
for Bluetooth keeps getting better and better,
making it a wireless technology that will be around
for years and years to come.

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Bluetooth Specifications

Below, you’ll find several specifications for the
well known Bluetooth:

1. Throughout the United States and even Europe,
the range of frequency is 2,400 – 2,483.5 MHZ, with
79 1-MHz RF (radio frequency) channels. The
frequency range in Japan is 2,472 to 2,497 MHz with
23 1-MHz RF channels.

2. A data channel of Bluetooth randomly hops 1,600
times per second between the 79 RF channels.

3. Each Bluetooth channel is divided into time
slots, with each one being 625 microseconds long.

4. A Bluetooth piconet has one master and up to
seven slaves. The master will transmit in even
time slots, while the slaves will transmit in odd
time slots.

5. The data in a single packet can be up to 2,745
bits in length.

6. Currently, there are two types of data transfer
between devices – SCO (synchronous connection
oriented) and ACL (asynchronous connectionless).

7. In a Bluetooth piconet, there can be up to
three SCO links containing 64,000 bits per second
with each one. To help avoid collision and timing
problems, the links of the SCO will use reserved
slots set up by the master.

8. A master can support up to three SCO links
with either one, two, or even three slaves.

9. The slots not reserved for the SCO links can
be used for ACL links.

10. A single master and slave can have one ACL
link.

11. ACL is either master to one slave (point to
point) or it broadcasts to all of the slaves.

12. The ACL slaves will only transmit when it has
been requested by the master. If the master doesn’t
make the request, the ACL slaves won’t transmit
anything at all.

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Bluetooth Security

These days, all communication technology faces the
issue of privacy and identity theft, with Bluetooth
being no exception. Almost everyone knows that email
services and networks require security. What users
of Bluetooth need to realize is that Bluetooth also
requires security measures as well.

The good news for Bluetooth users is that the
security scares, like most scares, are normally over
dramatized and blown entirely out of proportion. The
truth being told, these issues are easy to manage,
with various measures already in place to provide
security for Bluetooth technology.

It’s true that there has been some Bluetooth phones
that have been hacked into. Most devices that are
hacked into are normally those that don’t have any
type of security at all.

According to Bluetooth specialists, in order to hack
into a Bluetooth device, the hacker must:
1. Force two paired devices to break their
connection.
2. Steal the packets that are used to
resend the pin.
3. Decode the pin.

Of course, the hacker must also be within range of
the device, and using very expensive developer type
equipment. Most specialists recommend that you
have a longer pin, with 8 digits being recommended.

Fundamentals of security
The « pairing process » is one of the most basic levels
of security for Bluetooth devices. Pairing, is
two or more Bluetooth devices that recognize each
other by the profiles they share – in most cases
they both must enter the same pin.

The core specifications for Bluetooth use an
encryption algorithm, which is completely and entirely
secure. Once the devices pair with each other,
they too become entirely secure.

Until they have successfully paired, the Bluetooth
devices won’t communicate with each other. Due to
this pairing process and the fact that it is short
range – Bluetooth technology is considered to be
secure.

As the news has indicated, experienced hackers
have developed ways to get around this level of
basic security. There are ways to get around this
threat, as you can install software to prevent
hackers from getting in.

With Bluetooth becoming more and more popular, it’s
really no wonder that security is always in
question. As Bluetooth gets bigger and better,
security will always be something that no one
really takes lightly.

If you’ve been concerned about Bluetooth security
in the past, rest assured that newer devices will
offer bigger and better security. Preventing
hackers from getting in is something every owner
is concerned about – and the manufacturer’s are
very aware.

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Bluetooth Profiles

The profile found in Bluetooth will describe how
the technology is used. Profiles can be best
described as vertical slices through the protocol
stack. It will define options in each protocol
that are mandatory for the profile.

The profile will also define the parameter ranges
for each protocol. The concept of the profile is
used to decrease the risk of interoperability
problems between the different products. These
profiles won’t normally define any additions to
the Bluetooth specification, which is why you can
add new profiles where you need them. The
Bluetooth underlying technology is the same, only
the specific method that it’s used is defined.

Generally speaking, all profiles of Bluetooth are
based on the GAP (Generic Access Profile). There
are 9 profiles that fall in the GAP category, and
they are below:
1. AVRCP – Audio/Video Remote Control
Profile
2. ESDP – Extended Service Discovery Profile
3. CIP – Common ISDN Access Profile
4. PAN – Public Area Network Profile
5. HCRP – Hardcopy Cable Replacement
Profile
6. GAVDP – Generic Audio/Visual Distribution
Profile
7. A2DP – Advanced Audio Distribution Profile
8. VDP – Video Distribution Profile
9. HID – Human Interface Device Profile

To put it another way, usage models will describe
Bluetooth device applications and the associated
profiles that are used. The usage model focuses
mainly on three categories – voice/data access points,
peripheral interconnects, and PAN (Personal Area
Networking).

The voice and data access points involve connecting
computing devices to communicating devices through
a wireless link. This way, data can be transferred
in a wireless manor, without the need of cables or
other types of connectivity.

PAN is another very important usage model with
strong appeal to business customers. Bluetooth
networks are easy to set up in virtually any type
of environment. An example would be meeting
others at a trade show.

Instead of having contact information beamed via
infrared, business cards can quickly and easily be
transferred via Bluetooth wireless. The fact is
that many documents can be exchanged this very
same way – making the uses and possibilities
virtually endless.

The Bluetooth profile is very important to the
specification, as it enables you to do so much
more. You can use peripherals and devices with
the profiles, and virtually anything else that you
decide.

As Bluetooth expands and gets bigger and better,
you can count on the profiles to expand and get
even more functions. If you have experience with
Bluetooth profiles, you should know exactly what
they are and what you can do with them. If not,
all you need is a Bluetooth device – and a vivid
imagination.

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Bluetooth Operation

The networking standards of Bluetooth will transmit
data via low power radio frequency. Bluetooth
communicates on a 2.45 GHz frequency. This very
band of frequency has been set aside by international
agreement for the use of industrial and medical
devices.

Many devices that you already known and use take
advantage of this frequency band. Garage door
openers, baby monitors, and the next generation of
mobile phones all use this frequency within the ISM
band. Ensuring that Bluetooth and the other
devices don’t interfere with each other is a crucial
part of the design process.

One of the ways Bluetooth will avoid interfering
with other electronic devices is by sending out
weak signals of around 1 mw. In comparison, even
the most powerful of cell phones can transmit a
signal of 3 watts.

The low power signals will limit the range of a
Bluetooth device to around 32 feet, which cut the
chances of interference between your computer and
other electronic devices. Even though it has low
power, Bluetooth doesn’t require a line of sight
between the communicating devices. The walls in
your home won’t stop the signal, making it great
for rooms throughout the house.

Bluetooth can connect 8 devices at the same time.
With each of those devices on the same radius,
you may think they would interfere with each
other, although it’s very unlikely. Bluetooth
utilizes a technique known as low frequency
hopping, which makes it harder for more than
one device to transmit on the same frequency
at the same time.

With this technique, a device will use 79
individual, randomly chosen frequencies within
a designated range, which change from one another
on a regular basis.

In the case of Bluetooth, the transmitters will
change frequency 1,600 times or more every
second, meaning that more devices can make full
use of the radio spectrum. Since every
transmitter of Bluetooth will use spread spectrum
automatically, it’s very unlikely that two
transmitters will be on the same frequency at the
exact same time.

When the Bluetooth devices come within close range
of each other, an electronic conversation will
occur to determine whether or not they have
data to share or whether one needs to take total
control. The user doesn’t have any buttons to
press or commands to give – as the conversation
will occur automatically.

Once the conversation has occured, the devices
will form a network. Bluetooth devices will
create a PAN (Personal Area Network) or piconet
that may fill a room. Once the piconet has been
established, the devices will randomly hop in
frequencies.

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Bluetooth In Action

In the United States, Bluetooth gets absolutely no
respect. It is however, becoming more and more
common in notebooks, PDAs, and especially cell
phones. Bluetooth will provide wireless users a
way to transmit small amounts of data over short
distances.

Now, Bluetooth is facing stiff competition from
new wireless technology. Referred to as UWB or
Ultra Wideband, it promises data transfer of up
to 480 MB a second – while most current Bluetooth
devices transfer data up to 721 KB a second.

For the time being, Bluetooth devices are surely
cropping up. Below, we will look at some of
the accessories offered with Bluetooth technology.

Talking to the dashboard
When pairing it with a cell phone, the CCM Blue
Warrior car kit becomes a great speaker phone that
plugs into the power adapter of your vehicle. The
noise cancelling microphone will reduce background
noise efficiently, with the large buttons making
adjusting the speaker volume a snap. Although
the Blue Warrior is far from sexy or sleek, it’s
very practical.

Tiny tuning box
Part MP3 player and part hands free phone, the
compact and lightweight Sony HBM-30 is an attractive
gadget that lets you accept calls with minimal
interruption of your tunes. When you get an incoming
call it will automatically pause your music, then
you speak into the built in microphone that you
can wear around your neck or clip to your clothes.

The pen
With Nokia’s SU-1B digital pen, you can doodle and
make hand written notes in ink on a special pad
then transmit them from the pad to your Bluetooth
phone. Being an alternative to typing on a cell
phone keypad, the pen is very handy, although a
pricey tool from MMS fans.

Snapshots
If you want to make slide shows with your camera
photos, the Nokia SU-2 image viewer will let you
disply your pictures on a TV or projector. Simply
hook this square gray device to your TV’s input
with the built in cable, then beam the pictures
to the SU-2 from your Bluetooth enabled phone and
the photo fest will begin.

This device is a snap to set up and use, although
it displays resolutions of up to 640 by 480. If
you have a newer phone that takes high resolution
photos, you won’t be able to use the Nokia SU-2
image viewer.

Keep in mind, the 640 by 480 pixel photos will
appear blocky on TV screens, no matter what you
do. If your phone can send batches of photos, you
can create a slide show – although Nokia claims
you can use sequentially beamed shots as well.

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Bluetooth Glossary

Below, you’ll find a list of the most used terms in
Bluetooth technology. They can serve as a look up,
or to help you learn more about Bluetooth terms in
general.

2 in 1 handset
The situation where a subscriber’s handset is acting
as a remote handset to a base unit that provides a
network connection.

3G
Third generation, referring to the next generation
of digital phone technology.

802.11 WLAN
A wireless LAN specification defined by the IEEE.

Access code
Each base band packet will start with an access code,
which can be one of 3 types – CAC, DAC, and IAC.

ACK
Acknowledge.

ACL
Asynchronous Connectionless Link. This is one of the
two types of data links that are defined for Bluetooth.

ACO
Authenticated Ciphering Offset.

Active mode
During the active mode, the unit will actively
participate on the channel. The master will schedule
the transmission based on traffic demands from the
different slaves.

AP
Access point.

Authentification
The process of verifying who is at the opposite end
of the link.

Authentification device
A device whose identity has been verified during the
lifetime of the current link based on the
authentification procedure.

Baseband
This describes the specification of the digital
signal processing aspect of the hardware – the
controller – which carries out the baseband
protocols.

BB
Abreviation of baseband.

BD
Bluetooth device.

BER
Bit Error Rate.

The above is more of an intro to the terms that are
used with Bluetooth. Bluetooth currently has hundreds
of devices, making it the best wireless solution in
the world. With more coming out every day, you can
bet that Bluetooth will be around for many years to
come.

If you are new to Bluetooth, the terms used can be
very helpful. There are hundreds of glossary terms
that apply to Bluetooth, many of which describe
shortcuts to common terms. You can learn a lot by
reading over the meanings, especially if you have
never used Bluetooth technology before.

Those of you who have experience with Bluetooth,
can look over the glossary of terms to brush up
on your knowledge or just check out what an unfamiliar
term actually means. Nothing is complicated with
the meanings, although they make take some getting
used to.

Once you have been around Bluetooth for a while,
you’ll find yourself right at home with the terms
and meanings to the technology. All you need to do
is play around with it, and read books or manuals
whenever you get the chance. Before you know it,
you’ll be a professional in the vast world of
Bluetooth wireless.

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