Bluetooth profile

A Bluetooth profile is a wireless interface specification for Bluetooth-based communication between devices. In order to use Bluetooth technology, a device must be compatible with the subset of Bluetooth profiles necessary to use the desired services. A Bluetooth profile resides on top of the Bluetooth Core Specification and (optionally) additional protocols. While the profile may use certain features of the core specification, specific versions of profiles are rarely tied to specific versions of the core specification. For example, there are HFP 1.5 implementations using both Bluetooth 2.0 and Bluetooth 1.2 core specifications.

The way a device uses Bluetooth technology depends on its profile capabilities. The profiles provide standards which manufacturers follow to allow devices to use Bluetooth in the intended manner. For the Bluetooth low energy stack according to Bluetooth V4.0 a special set of profiles applies.

At a maximum, each profile specification contains information on the following topics:

• Dependencies on other formats
• Suggested user interface formats
• Specific parts of the Bluetooth protocol stack used by the profile. To perform its task, each profile uses particular options and parameters at each layer of the stack. This may include an outline of the required service record, if appropriate.

This article summarizes the current definitions and possible applications of each profile.

List of profiles

The following profiles are defined and adopted by the Bluetooth SIG:

Advanced Audio Distribution Profile (A2DP)

This profile defines how high quality audio (stereo or mono) can be streamed from one device to another over a Bluetooth connection. For example, music can be streamed from a mobile phone, to a wireless headset, hearing aid & cochlear implant streamer, or car audio or from a laptop/desktop to a wireless headset.

A2DP was initially used in conjunction with an intermediate Bluetooth transceiver that connects to a standard audio output jack, encodes the incoming audio to a Bluetooth-friendly format, and sends the signal wirelessly to Bluetooth headphones that decode and play the audio. Bluetooth headphones, especially the more advanced models, often come with a microphone and support for the Headset (HSP), Hands-Free (HFP) and Audio/Video Remote Control (AVRCP) profiles.

A2DP is designed to transfer a uni-directional 2-channel stereo audio stream, like music from an MP3 player, to a headset or car radio.^[1] This profile relies on AVDTP and GAVDP. It includes mandatory support for the low-complexity SBC codec (not to be confused with Bluetooth's voice-signal codecs such as CVSDM), and supports optionally: MPEG-1 , MPEG-2, MPEG-4, AAC, and ATRAC, and is extensible to support manufacturer-defined codecs, such as apt-X. Some Bluetooth stacks enforce the SCMS-T digital rights management (DRM) scheme. In these cases, it is impossible to connect certain A2DP headphones for high quality audio.

Audio/Video Remote Control Profile (AVRCP)

This profile is designed to provide a standard interface to control TVs, Hi-fi equipment, etc. to allow a single remote control (or other device) to control all of the A/V equipment to which a user has access. It may be used in concert with A2DP or VDP.

It has the possibility for vendor-dependent extensions.

AVRCP has several versions with significantly increasing functionality:

• 1.0—Basic remote control commands (play/pause/stop, etc.)
• 1.3—all of 1.0 plus metadata and media-player state support
  • The status of the music source (playing, stopped, etc.)
  • Metadata information on the track itself (artist, track name, etc.).
• 1.4—all of 1.0, 1.3, plus media browsing capabilities for multiple media players
  • Browsing and manipulation of multiple players
  • Browsing of media metadata per media player, including a "Now Playing" list
  • Basic search capabilities

Basic Imaging Profile (BIP)

This profile is designed for sending images between devices and includes the ability to resize, and convert images to make them suitable for the receiving device. It may be broken down into smaller pieces:

Image Push 

Allows the sending of images from a device the user controls.

Image Pull 

Allows the browsing and retrieval of images from a remote device.

Advanced Image Printing 

print images with advanced options using the DPOF format developed by Canon, Kodak, Fujifilm, and Matsushita

Automatic Archive 

Allows the automatic backup of all the new images from a target device. For example, a laptop could download all of the new pictures from a camera whenever it is within range.

Remote Camera 

Allows the initiator to remotely use a digital camera. For example, a user could place a camera on a tripod for a group photo, use their phone handset to check that everyone is in frame, and activate the shutter with the user in the photo.

Remote Display 

Allows the initiator to push images to be displayed on another device. For example, a user could give a presentation by sending the slides to a video projector.

Basic Printing Profile (BPP)

This allows devices to send text, e-mails, vCards, or other items to printers based on print jobs. It differs from HCRP in that it needs no printer-specific drivers. This makes it more suitable for embedded devices such as mobile phones and digital cameras which cannot easily be updated with drivers dependent upon printer vendors.

Common ISDN Access Profile (CIP)

This provides unrestricted access to the services, data and signalling that ISDN offers.

Cordless Telephony Profile (CTP)

This is designed for cordless phones to work using Bluetooth. It is hoped that mobile phones could use a Bluetooth CTP gateway connected to a landline when within the home, and the mobile phone network when out of range. It is central to the Bluetooth SIG's '3-in-1 phone' use case.

Device ID Profile (DIP)

This profile allows a device to be identified above and beyond the limitations of the Device Class already available in Bluetooth. It enables identification of the manufacturer, product id, product version, and the version of the Device ID specification being met. It is useful in allowing a PC to identify a connecting device and download appropriate drivers. It enables similar applications to those the Plug-and-play specification allows.

Dial-up Networking Profile (DUN)

This profile provides a standard to access the Internet and other dial-up services over Bluetooth. The most common scenario is accessing the Internet from a laptop by dialing up on a mobile phone, wirelessly. It is based on Serial Port Profile (SPP), and provides for relatively easy conversion of existing products, through the many features that it has in common with the existing wired serial protocols for the same task. These include the AT command set specified in European Telecommunications Standards Institute (ETSI) 07.07, and Point-to-Point Protocol (PPP).

DUN distinguishes the initatior (DUN Terminal) of the connection and the provider (DUN Gateway) of the connection. The gateway provides a modem interface and establishes the connection to a PPP gateway. The terminal implements the usage of the modem and PPP protocol to establish the network connection. In standard phones, the gateway PPP functionality is usually implemented by the access point of the Telco provider. In "always on" smartphones, the PPP gateway is often provided by the phone and the terminal shares the connection.

Fax Profile (FAX)

This profile is intended to provide a well-defined interface between a mobile phone or fixed-line phone and a PC with Fax software installed. Support must be provided for ITU T.31 and / or ITU T.32 AT command sets as defined by ITU-T. Data and voice calls are not covered by this profile.

Generic Audio/Video Distribution Profile (GAVDP)

Provides the basis for A2DP, and VDP.

Generic Access Profile (GAP)

Provides the basis for all other profiles. GAP defines how two Bluetooth units discover and establish a connection with each other.

Generic Object Exchange Profile (GOEP)

Provides a basis for other data profiles. Based on OBEX and sometimes referred to as such.

Hard Copy Cable Replacement Profile (HCRP)

This provides a simple wireless alternative to a cable connection between a device and a printer. Unfortunately it does not set a standard regarding the actual communications to the printer, so drivers are required specific to the printer model or range. This makes this profile less useful for embedded devices such as digital cameras and palmtops, as updating drivers can be problematic.

Health Device Profile (HDP)

Profile designed to facilitate transmission and reception of Medical Device data. The API's of this layer interact with the lower level Multi-Channel Adaptation Protocol (MCAP layer), but also perform SDP behavior to connect to remote HDP devices. Also makes use of the Device ID Profile (DIP).

Hands-Free Profile (HFP)

Currently in version 1.5, this is commonly used to allow car hands-free kits to communicate with mobile phones in the car. It uses SCO to carry a monaural audio channel with continuously variable slope delta modulation or pulse-code modulation, and with logarithmic a-law or μ-law quantization.

In 2002 Audi, with the Audi A8, was the first motor vehicle manufacturer to install Bluetooth technology in a car, enabling the passenger to use a wireless in-car phone. The following year DaimlerChrysler and Acura introduced Bluetooth technology integration with the audio system as a standard feature in the third-generation Acura TL in a system dubbed HandsFree Link (HFL). Later, BMW added it as an option on its 1 Series, 3 Series, 5 Series, 7 Series and X5 vehicles. Since then, other manufacturers have followed suit, with many vehicles, including the Toyota Prius (since 2004), 2007 Toyota Camry, 2007 Infiniti G35, and the Lexus LS 430 (since 2004). Several Nissan models (Versa, X-Trail) include a built-in Bluetooth for the Technology option. Volvo started introducing support in some vehicles in 2007, and as of 2009 all Bluetooth-enabled vehicles support HFP.^[2]

The Bluetooth car kits allow users with Bluetooth-equipped cell phones to make use of some of the phone's features, such as making calls, while the phone itself can be left in the user's pocket or hand bag. Companies like Nokia, Johnson Controls, Peiker acustic, RAYTEL, Parrot, Novero, S1NN and Motorola manufacture Bluetooth hands-free car kits for well-known brand car manufacturers.

Most bluetooth headsets implement both Hands-Free Profile and Headset Profile, because of the extra features in HFP for use with a mobile phone, such as last number redial, call waiting and voice dialing.

Human Interface Device Profile (HID)

Provides support for devices such as mice, joysticks, keyboards, as well as sometimes providing support for simple buttons and indicators on other types of devices. It is designed to provide a low latency link, with low power requirements. PlayStation 3 controllers and Wii Remotes also use Bluetooth HID.

Bluetooth HID is a lightweight wrapper of the Human Interface Device protocol defined for USB. The use of the HID protocol simplifies host implementation (ex: support by Operating Systems) by enabling the re-use of some of the existing support for USB HID to also support Bluetooth HID.,

Headset Profile (HSP)

This is the most commonly used profile, providing support for the popular Bluetooth Headsets to be used with mobile phones. It relies on SCO for audio encoded in 64 kbit/s CVSD or PCM and a subset of AT commands from GSM 07.07 for minimal controls including the ability to ring, answer a call, hang up and adjust the volume.

Intercom Profile (ICP)

This is often referred to as the walkie-talkie profile. It is another TCS (Telephone Control protocol Specification)^[3] based profile, relying on SCO to carry the audio. It is proposed to allow voice calls between two Bluetooth capable handsets, over Bluetooth.

LAN Access Profile (LAP)

LAN Access profile makes it possible for a Bluetooth device to access LAN, WAN or Internet via another device that has a physical connection to the network. It uses PPP over RFCOMM to establish connections. LAP also allows the device to join an ad-hoc Bluetooth network.

The LAN Access Profile has been replaced by the PAN profile in the Bluetooth specification.

Message Access Profile (MAP)

Message Access Profile (MAP)^[4] specification allows exchange of messages between devices. Mostly used for automotive handsfree use. The MAP profile can also be used for other uses that require the exchange of messages between two devices.

Object Push Profile (OPP)

A basic profile for sending "objects" such as pictures, virtual business cards, or appointment details. It is called push because the transfers are always instigated by the sender (client), not the receiver (server).

OPP uses the APIs of OBEX profile and the OBEX operations which are used in OPP are connect, disconnect, put, get and abort. By using these API the OPP layer will reside over OBEX and hence follow the specifications of the Bluetooth stack.

Personal Area Networking Profile (PAN)

This profile is intended to allow the use of Bluetooth Network Encapsulation Protocol on Layer 3 protocols for transport over a Bluetooth link.

Phone Book Access Profile (PBAP, PBA)

Phone Book Access (PBA)^[5][6] or Phone Book Access Profile (PBAP) is a profile that allows exchange of Phone Book Objects between devices. It is likely to be used between a car kit and a mobile phone to:

• allow the car kit to display the name of the incoming caller;
• allow the car kit to download the phone book so the user can initiate a call from the car display.

Serial Port Profile (SPP)

This profile is based on ETSI 07,10 and the RFCOMM protocol. It emulates a serial cable to provide a simple substitute for existing RS-232, including the familiar control signals. It is the basis for DUN, FAX, HSP and AVRCP.

Service Discovery Application Profile (SDAP)

SDAP describes how an application should use SDP to discover services on a remote device. SDAP requires that any application be able to find out what services are available on any Bluetooth enabled device it connects to.

SIM Access Profile (SAP, SIM, rSAP)

This allows devices such as car phones with built in GSM transceivers to connect to a SIM card in a phone with Bluetooth, thus the car phone itself doesn't require a separate SIM card. This profile is also known as rSAP (remote-SIM-Access-Profile). More information on which phones are supported can be found here(German version only)

Synchronisation Profile (SYNCH)

This profile allows synchronisation of Personal Information Manager (PIM) items. As this profile originated as part of the infrared specifications but has been adopted by the Bluetooth SIG to form part of the main Bluetooth specification, it is also commonly referred to as IrMC Synchronization.

Video Distribution Profile (VDP)

This profile allows the transport of a video stream. It could be used for streaming a recorded video from a PC media center to a portable player, or a live video from a digital video camera to a TV. Support for the H.263 baseline is mandatory. The MPEG-4 Visual Simple Profile, and H.263 profiles 3 and 8 are optionally supported, and covered in the specification.1

Wireless Application Protocol Bearer (WAPB)

This is a profile for carrying Wireless Application Protocol (WAP) over Point-to-Point Protocol over Bluetooth.

Comments

These profiles are still not finalised, but are currently proposed within the Bluetooth SIG:

• Unrestricted Digital Information (UDI)
• Extended Service discovery profile (ESDP)^[7]
• Video Conferencing Profile (VCP) : This profile is to be compatible with 3G-324M, and support videoconferencing over a 3G high-speed connection.

Compatibility of products with profiles can be verified on the Bluetooth Qualification Program website.

See also

• Bluetooth
• Bluetooth protocols

References

1. ^ "Bluetooth Tutorial - Profiles". palowireless Pty Ltd. http://www.palowireless.com/infotooth/tutorial/profiles.asp. Retrieved 2007-01-05. 
2. ^ "Bluetooth FAQ – Wireless In-Car Mobile Phone Technology – Volvo". http://www.volvocars.com/au/sales-services/sales/car-devices/bluetooth/pages/faq.aspx. Retrieved 27 Apr 2010. "phones must have the Bluetooth hands-free profile to be able to connect with the Volvo vehicle." 
3. ^ "Bluetooth Glossary". http://www.palowireless.com/infotooth/glossary.asp#SR. 
4. ^ Message Access Profile_SPEC_V10
5. ^ PBA - Phone Book Access, Definition
6. ^ PBAP_SPEC_V11r00
7. ^ Extended Service Discovery Profile

External links

• Official website
• Specification: Adopted Documents, The Official Bluetooth SIG Member Website