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Bluetooth Profiles |
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Are you confused by the
alphabet soup of different acronyms used to describe
Bluetooth features and functions?
Part
of a series on Bluetooth -
more articles listed on the right. |
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
Compared
Bluetooth is basically a
wireless way of connecting any two devices together. Think
of it as nothing more than an invisible, stretchy wire.
Now, in theory, you can
connect all sorts of devices up with normal wires.
Sometimes through, there's not a lot of sense in connecting two
devices together, or, even if they can be connected together,
nothing will happen. For example, maybe you have a scanner
and a thumb drive. You can connect them together, but
nothing will happen. You can't command the fax machine to
scan from the thumb drive, and neither can the fax machine
browse or do anything to any data already on the thumb drive.
What is needed, any time two
devices are connected, is some sort of common language for the
two units to share, and some sort of way of then being able to
control the two units.
For example, slightly change
the scanner/thumb drive example. Let's consider instead a
scanner connected to a computer. As you know, after you've
connected your scanner to your computer, you can then go to your
scanning program and tell the scanner to scan an image and send
it to the computer. Sometimes also you can press a speed
button on the scanner that will automatically do a scan and send
the scan to the computer without you having to first start the
scan program on the computer.
And, in addition to the scan
program that might come with the scanner that you load onto the
computer, other programs on the computer might also be able to
communicate directly with the scanner through various scanner
drivers.
The same thing holds true
with Bluetooth, it is just that the terms and concepts are
described slightly differently.
Bluetooth itself is
basically just the 'wire' that connects any two devices.
To then allow the two devices to be able to communicate, they
need to have the same 'Bluetooth profile' loaded on each of
them. This profile can be thought of like the programs
that, eg, allow a computer to control a scanner and possibly
vice versa.
The ability of - for
example, your cell phone - to be able to talk to your camera,
your printer, your headset, and who knows what else depends on
the profiles that it and the other device both have loaded.
To start off the discussion,
here is a table to show the major differences betmally 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
PDA.
https://en.wikipedia.org/wiki/Bluetooth_profile
https://en.wikipedia.org/wiki/Bluetooth_protocols
https://en.wikipedia.org/wiki/Bluetooth
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A2DP (Advanced Audio Distribution
Profile) |
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This
profile defines how music is sent from
one device to another. Music or
other audio is sent from a source (SRC)
to a sink (SNK).
The
term 'advanced' means that it supports
higher quality audio than do the more
basic headset and hands-free profiles.
Audio can be mono or stereo, and is of
CD quality. |
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AVRCP (Audio Video Remote Control
Profile) |
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This
profile allows commands to be sent from
a device to another device so as to
control the second device - allowing
functions such as play/pause/stop and so
on, and more advanced functions such as
sending information about the music
being played.
There are several versions of this
protocol. Version 1.0 allows for
basic command functionality only.
Versions 1.3 and 1.4 allow for
increasing exchange of 'metadata'
information - ie information about the
track being played (name of song,
performers, etc) and about other tracks
that might also be available to be
played to (for searching, etc). |
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BIP (Basic Imaging Profile) |
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Although it says 'basic', this is a
fairly sophisticated profile that allows
for images to be sent between devices.
It
is sophisticated because in addition to
straightforward copying of images, it
allows both for images to be sent to
another device ('Image Push') and
to be requested and taken from another
device ('Image Pull').
Images can also be resized and converted
to better suit the new device.
In
addition, this profile can allow a
camera to be remotely activated ('Remote
Camera'). |
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BPP (Basic Printing Profile) |
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This
allows for sending print jobs to
printers. It uses a generic
standard printer driver, unlike the HCRP
profile which requires specific printer
drivers for all printers connected to. |
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CIP (Common ISDN Access Profile) |
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This
allows devices to connect to ISDN
equipment and to understand/exchange the
data and signaling information required
in such cases.
ISDN
these days is not very common. |
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CTP (Common Telephony Profile) |
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This
is currently (2009) a rather futuristic
profile, and related to allowing
cordless phones to communicate to their
bases via Bluetooth.
More
relevantly, enables a cellphone equipped
with this profile to switch to a
cordless cellphone mode rather than
using the wireless service provider's
signal when within range of a
matching/paired cordless phone base
station. |
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DID (Device ID Profile) |
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Bluetooth has some built in protocols
that enable devices to tell each other
what they are.
The
DID provides further capabilities in
addition to these basic capabilities.
It can provide more detailed specifics
about the product and version being
described, and as such, allows for other
devices to understand how to configure
themselves to work with the device (and
where/how to download device drivers) in
a type of USB-like plug-and-play. |
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DUN (Dial Up Networking Profile) |
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Remember modems and dialing up over
phone lines to access the internet?
It seems so, well, 'twentieth century'
doesn't it, but some people still use
such capabilities.
The
DUN allows for typically a cellphone to
be considered as a modem connected to
another device (typically a laptop
computer) and to then be controlled to
dial out and connect to the internet,
using many of the more or less standard
'AT' modem commands.
This
is an extension/special case of the SPP
(see below). |
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FAX (Fax Profile) |
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A
FAX profile allows a device such as a
cellphone to receive or send a fax call
and to then pass (receive) the fax data
on to or from another device such as a
PC that is running fax software.
This
profile together with the appropriate
software to send/receive the fax on a
computer can make your phone and its
phone number into a fax machine as well
as a voice and data phone.
But
if you're considering the need to
receive faxes, maybe better to use a
free service such as kall8.com and keep
it away from your phone entirely. |
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FTP (File Transfer Profile) |
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The
FTP protocol allows a device to browse,
send and receive files and folders
between itself and another device that
it is paired to.
FTP
is an extension of the GOEP profile. |
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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
reality.
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 new
Bluetooth 2.0 standard, allowing for three to ten times faster
network speeds, and more careful use of battery power, is slowly
becoming available.
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
official
Bluetooth website. And here is a
very
useful site full of information on how to get Bluetooth devices
communicating with each other and your PC.
Bluetooth Range
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).y,
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
this website.
Summary
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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Originally published
25 Sep 2009, last update
21 Jul 2020
You may freely reproduce or distribute this article for noncommercial purposes as long as you give credit to me as original writer.
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