Bluetooth

The Bluetooth Solution

The technology of Bluetooth will take small area
networking to the next level by removing the need
for user intervention and help keep transmission
power very low to preserve battery power. Each
transmission signal to and from your cellular
phone will use just 1 mw of power, giving you
plenty of space on your battery to talk.

Bluetooth is a networking standard that will
work on two levels:
1. It will provide agreement at the
physical level, as Bluetooth is a radio frequency
standard.
2. It will provide agreement at the level
of protocol, where products will have to agree
on when bits are sent, how many are sent, and how
the parties in conversation can be sure the message
recieved is the same one that was sent.

The major draws to Bluetooth is the fact that
it’s wireless, inexpensive, and automatic. There
are other ways to get around wires, including
infrared. Infrared uses light waves of a lower
frequency than the human eye can, and is normally
used in television remote controls.

The technology of Bluetooth is intended to get
around the problems that normally come with
infrared systems. The 1.0 older standard of
Bluetooth has a max transfer speed of 1 MB a
second, while the 2.0 Bluetooth standard can
manage up to 3.0 MB a second. To make things
better, 2.0 is compatible with 1.0 devices.

As a solution to wireless, Bluetooth will
eliminate the need for messy cords, keeping
everything nice and neat. It’s perfect for those
who like to talk on cell phones, as you no
longer need to hold the phone next to your
ear – which is great for those who travel a
lot.

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Key Learning Points Of Bluetooth

Bluetooth is easily the best in wireless handheld
technology. When it comes to learning, Bluetooth
can get quite complicated. To help you, you’ll find
the key learning points of Bluetooth below:

1. Bluetooth is an energy efficient, low
overhead communication protocol that’s ideal for
interdevice communications.
2. Unlike infrared, Bluetooth doesn’t require
a line of sight.
3. Depending on the implementation, Bluetooth
can have a range of up to 100 meters.
4. The specification of Bluetooth consists of
a Foundation Profile Document and a Foundation Core
Document.
5. The protocol stack for Bluetooth consists
of core protocols, cable protocols, and even adapted
protocols.
6. The transmitter operates around the 2.4
GHz frequency band.
7. The data channel will change frequency, or
hops, 1,600 times in a second, between the 79 allocated
channels in the ISM band.
8. Bluetooth utilizes a spread spectrum
frequency hopping RF characteristic to ensure that
independant networking operates when the other
devices are in range.
9. A piconet is formed when one or more
devices open up a channel of communication.
10. A piconet can have a master and up to
seven slaves.
11. Communication of the interdevice is
based on the concepts of channels.
12. All Bluetooth devices are capable of
transmitting voice.
13. The channel has a total capacity of
1 MB per second.
14. There are two types of channels with
Bluetooth – SCO (Synchronous Connection Oriented) and
ACL (Asynchronous Connectionless).
15. The SCO channels are time oriented, and
are therefore primarily used for transferring time
critical data such as voice.
16. ACL channels are normally used for
communicating data.
17. Data contained in a packet can be up to
2,745 bits in length.
18. In a single piconet, there can be up
to three SCO links containing 64,000 bits a second
each.
19. To avoid collision and timing problems,
SCO links are reserved slots that are set up by
the master.
20. The masters can support up to three
SCO links with either one, two, or three slaves.
21. The slots that aren’t reserved for SCO
links can be used as ACL links.
22. The LMP (Link Management Protocol)
will handle link level security, error corrections,
and the establishment of communications links.
23. The LMP packets will have priority
over user packets that originate and form the
L2CAP layer.
24. The L2CAP layer will ensure an
acceptable quality of service.
25. No more than one ACL link can exist
at the L2CAP layer.

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Introduction To Bluetooth

Bluetooth was designed to allow low bandwidth wireless
connections to become easy to use so even those who
are new to wireless can use them. Version 1.1 of
Bluetooth describes a low power, short range wireless
networking technology that uses radio waves to send
data at rates up to 720 kilobits a second.

The specification for Bluetooth provides for different
classes of radio that allow transmission ranges of
up to 100 meters by boosting the radio power. The
technology of Bluetooth isn’t limited to line of
sight transmission since it uses directional waves
that are capable of transmitting through many
obstructions.

Bluetooth is an industry standard communication of
wireless, meaning that it enables the connection
of other devices as well, such as cell phones,
computers, digital cameras, and other types of
electronic devices. The specification of Bluetooth
defines a radio system and a « stack » of protocol
layers and profiles. The highest layer is the
application layer, while the lowest layer is the
radio.

The wireless technology of Bluetooth is positioned
to revolutionize the personal connectivity market
by providing freedom from inconvenient fixed type
lines.

The specification for Bluetooth eliminates the need
for cables by providing a small form factor, low
cost wireless solution that will link computers,
cell phones, and other electronics. Bluetooth
also allows users to connect many ranges of devices
quickly and easily and expands communications
capabilities as well.

The size of the Bluetooth radio is amazing, as a
Bluetooth radio can be built into one or two very
small microchips then integrated into any electronic
device where wireless operations would be an
advantage.

Bluetooth also offers a robust link, which ensures
that normal operating circumstances are not
interrupted by interference from other signals
that are operating in the same frequency band.

Also known for its worldwide operation, Bluetooth
radio operates in the 2.4 GHz frequency band, which
is license free and available to any type of
radio system in the world. No matter where you
are in the world, you count on Bluetooth to work.

Security is also important. Offering advanced
security mechanisms, Bluetooth ensures a high level
of security. Therefore, authentification will
prevent unauthorized acess to important data and
make it very difficult to listen in.

Bluetooth also boasts power optimization. The radio
is power friendly and the software for Bluetooth
is very configurable, limiting the power consumption
of equipment. The radio itself only consumes a
small amount of power from a cellular phone.

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How Bluetooth Works

Bluetooth devices will normally operate at 2.4 GHZ
in the license free, globally available ISM radio
band. The advantage to this band includes worldwide
availability and compatibility. A disadvantage to
this however, is that the devices must share this
band with other RF emitters. This includes
automobile security systems, other wireless devices,
and other noise sources, such as microwaves.

To overcome this challenge, Bluetooth employs a
fast frequency hopping scheme and therefore uses
shorter packets than other standards within the
ISM band. This scheme helps to make Bluetooth
communication more robust and more secure.

Frequency hopping
Frequency hopping is basically jumping from frequency
to frequency within the ISM radio band. After a
bluetooth device sends or receives a packet, it
and the device (or devices) it’s communicating with
hop to another frequency before the next packet is
sent. This scheme offers three advantages:
1. Allows Bluetooth devices to use the
entirety of the available ISM band, while never
transmitting from a fixed frequency for more than a
short period of time. This helps insure that
Bluetooth conforms to the ISM restrictions on the
transmission quantity per frequency.
2. Ensures that any interference won’t
last long. Any packet that doesn’t arrive safely
to its destination can be resent to the next
frequency.
3. Provides a base level of security as
it’s very hard for an eavesdropping device to predict
which frequency the Bluetooth devices will use
next.

The connected devices however, must agree upon the
frequency they will use next. The specification
in Bluetooth ensures this in two ways. First, it
defines a master and slave type relationship between
bluetooth devices. Next, it specifies an algorithm
that uses device specific information when
calculating the frequency hop sequences.

A Bluetooth device that operates in master mode can
communicate with up to seven devices that are set in
slave mode. To each of the slaves, the master
Bluetooth device will send its own unique address
and the value of its own internal clock. The
information sent is then used to calculate the
frequency hop sequences.

Because the master device and each of the slave
devices use the same algorithm with the same initial
input, the connected devices will always arrive
together at the next frequency that they have agreed
upon.

As a replacement for cable technology, it’s no
wonder that Bluetooth devices are usually battery
powered, such as wireless mice and battery powered
cell phones. To conserve the power, most devices
operate in low power. This helps to give Bluetooth
devices a range of around 5 – 10 meters.

This range is far enough for wireless communication
but close enough to avoid drawing too much power
from the power source of the device.

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Connecting Many With Bluetooth

Constantly evolving, the technology of Bluetooth
started off as a basic wireless connection standard
but has since then been adapted and proven with many
different uses and functions.

A good example is Bluetooth for cell phones. It
enables mobile users to connect to their hands free
headset without using wires. Bluetooth technology
will also allow mobile phone users to connect
with their hands free kit as well.

Another handy use of Bluetooth is file sharing. It
allows the sharing of files between two cell phones,
between a cell phone and computer, which makes the
sharing of files a snap. If you have a cell phone
and computer, you can easily transfer data between
the two.

Say for example you wanted to put an MP3 on your
phone from your computer you could do it easily
with Bluetooth. All you would need is a Bluetooth
adapter for your computer. It doesn’t stop with the
swapping of files either,as you can use your computer
and phone to synchronise phone books, send SMS messages,
and much more.

Although Bluetooth may be dandy for cell phones,
it also comes in handy for the home office as well.
Utilizing Bluetooth is a great way to set up a
home office – two computers, a printer, and even a
scanner. They all can be connected using Bluetooth
technology with effective ranges of up to 10 meters.

The technology and devices of Bluetooth will be
around for years and years to come. As years go
by, Bluetooth will provide even better wireless
solutions for different applications. Even though
Bluetooth has a short range, it has that short
range for a reason. Bluetooth is easily the best
in wireless technology – which it continues to
prove time and time again.

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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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