What is Bluetooth?

Bluetooth is a way of wirelessly transferring data from one device to another. Bluetooth first appeared around ten years ago as a quicker and easier method of data transfer than infra-red. With infra-red you had to point two devices together in order for it to work (the same way as you have to point your television remote at your TV.) There were a number of problems with this kind of connection; it was unstable, slow and limited in its uses. With Bluetooth, you no longer have to line up two devices, you just simply turn on Bluetooth and send to the device you want. Bluetooth technology was initially used for personal hands free kits. The lack of wires made it much more convenient – especially when driving. Over the last few years as prices have fallen and phones have advanced, Bluetooth’s increasing range and even faster speeds has meant it could be used for far more than just hands free kits.
 

Bluetooth-classes

Class 1 - up to 100m

Class 2 - up to 10m

Class 3 - less than 10m

In order to achieve data communication at these distances you will need both devices to be from the same class.

So what can it do?

Bluetooth is most commonly used for transferring pictures, music and ringtones between phones and connecting to Bluetooth headsets, personal hands free kits and car kits. As more and more phones become multimedia handsets, Bluetooth can also be used to stream music in stereo to wireless speakers and car kits using A2DP technology. With the introduction of Internet Telephony, Bluetooth headsets are now being used with Home PCs to enable wireless calling.

Bluetooth Profiles

Advanced Audio Distribution Profile (A2DP)

The A2DP profile describes how stereo quality audio can be streamed from a media source. A typical usage scenario can be considered as the “walkman” class of media player. The audio source would be the music player and the audio output is the wireless headset. A2DP defines the protocols and procedures that allow the distribution of high quality audio content in mono or stereo.

Audio / Video Remote Control Profile (AVRCP)

AVRCP is designed to provide a standard interface to control TVs, Hifi equipment, etc… This profile is used to allow a single remote control (or other device) to control all the A/V equipment that a user has access to. AVRCP defines how to control characteristics of streaming media. This includes pausing, stopping, starting playback and volume control as well as other types of remote control operations.

Dial-up Networking Profile (DUN)

DUN provides a standard to access the Internet and other dial-up services via Bluetooth wireless technology. The most common scenario is accessing the Internet from a laptop by dialling up on a mobile phone, wirelessly.

Generic Object Exchange Profile (GOEP)

GOEP is used to transfer an object from one device to another. The object may be any object such as a picture, document, business card, etc. The profile defines two roles, a server that provides the location from which an object is pulled or pushed, as well as a client that initiates the action. GOEP provides a generic blueprint for other profiles using the OBEX protocol.

Hands-Free Profile (HFP)

HFP describes how a gateway device can be used to place and receive calls for a handsfree device. A typical configuration is a car using a mobile phone as a gateway device. In the car, the stereo is used for the phone audio and a microphone is installed in the car for sending outgoing audio of the conversation. HFP is also used for a personal computer to act as a speakerphone for a mobile phone in a home or office environment.

Headset Profile (HSP)

The HSP describes how a Bluetooth enabled headset should communicate with a mobile phone or other Bluetooth enabled device such as a computer. When connected and configured, the headset can act as the remote device’s audio input and output interface.

Human Interface Device Profile (HID)

The HID profile defines the protocols, procedures and features to be used by Bluetooth enabled HID, such as keyboards, pointing devices, gaming devices, and remote monitoring devices. Sony Ericsson handsets support the HID profile.

Object Exchange (OBEX) Protokol

OBEX is a transfer protocol that allows devices to exchange files, such as Images, Videos and Music Files

Pairing

The process of establishing a new relationship between two Bluetooth enabled devices. During this process a passkey is exchanged either before connection establishment was requested or during connecting phase. Some devices will need to be put into “pairing mode” before pairing can begin.

Pairing mode

Most Bluetooth devices will need to be put into pairing mode before it can be linked to another device. During pairing mode the device will send out a signal that will allow it to be found by the device that is trying to link to it. By having a pairing mode it prevents unauthorised users from accessing a device.

Personal Area Networking Profile (PAN)

PAN describes how two or more Bluetooth enabled devices can form an ad-hoc network and how the same mechanism can be used to access a remote network through a network access point. The profile roles include the network access point, group ad-hoc network and personal area network user.

SIM Access Profile (SAP)

SAP allows devices such as car phones with built in GSM transceivers to connect to a SIM card in a Bluetooth enabled phone. Therefore the car phone itself does not require a separate SIM card.

Synchronization Profile (SYNC)

The SYNC profile is used in conjunction with GOEP to enable synchronization of calendar and address information (personal information manager (PIM) items) between Bluetooth enabled devices. A common application of this profile is the exchange of data between a PDA and computer.

What is Multipoint?

Multipoint is a new development in Bluetooth technology that allows your Bluetooth Headset to be connected to two Bluetooth devices at the same time. When a call comes in, the headset knows which handset is ringing and will connect to the phone automatically. Multipoint can benefit most Bluetooth Headset users. It is ideal if you have to carry around a work phone and a personal phone but don’t want the hassle of having two separate headsets. If you use VOIP telephony at home, but don’t want to be tied down to sitting in front of your PC, Multipoint means you can pair your compatible Bluetooth Headset to your PC and your mobile and no matter which phone rings, the call will come through to your headset. It’s not just business user that can benefit though, with more MP3 and music systems streaming music via Bluetooth, Multipoint means you can be listening to music on your Stereo Bluetooth Headset from your stereo or MP3 player, and when a call comes in, the music will pause/mute allowing you to answer the call on your mobile phone. Music playback will automatically resume once you end your call.
 

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