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Introduction To Bluetooth Profiles
One of the goals of Bluetooth was to create a standard technology that worked the same across a wide variety of consumer devices, likely coming from a wide variety of manufacturers. Furthermore, it is important that a device from one manufacturer is able to interoperate—that is, connect and communicate--with another Bluetooth device from another unrelated manufacturer. Without such standardization, companies would start developing and promoting their own Bluetooth standards which would create connection problems, delay or prevent adoption of Bluetooth, and generally cause confusion. To help ensure standardization and interoperability, the Bluetooth consortium not only defined the wireless radio standard, but also carefully defined standards for different applications of Bluetooth, which they named “profiles”.
Like most new technologies, the Bluetooth specification has gone through a few revisions already, including 1.0, 1.1, 1.2, and the currently available version, 2.0. Version 1.1 is still common on devices that are readily available, and is a good reference version for discussing the major Bluetooth profiles. (Version 1.2 is also relatively common and has similar functions as 1.1),. Version 1.1 has 13 profiles defined as follows:
Generic Access Profile (GAP): This profile which defines how two Bluetooth devices discover and establish communications with each other. The GAP profile does not define specific application functions for the user, but rather it is a base profile that defines the modes and procedures that all the other profiles use.
Service Discovery Application Profile (SDAP): As the name implies, this profiles allows Bluetooth devices to query the services available on other Bluetooth devices.
Cordless Telephony Profile (CTP): Defines how a Bluetooth device can be used as a cordless phone.
Intercom Profile: Defines how two Bluetooth phones can connect with each other directly without the use of the public telephone network.
Serial Port Profile (SPP): Defines how two Bluetooth devices can communicate with each other by using virtual serial ports. Using this profile, Bluetooth communication can be treated as just another serial communication.
Headset Profile (HS or HSP): The HSP describes how a Bluetooth wireless headset should communicate with another device, typically a Bluetooth phone but it could also be a PC or Personal Digital Assistance (PDA).
Dial-Up Networking Profile (DNP or DUN): Defines how a Bluetooth device can connect to a Bluetooth-enabled modem or mobile phone. The most common scenario is accessing the Internet from a laptop by dialing up on a mobile phone, wirelessly instead of through a cable from the laptop to the phone. It is based on the SPP.
Fax Profile (FP): Defines how a Bluetooth device can connect to a Bluetooth-enabled fax device, such as a fax machine or a fax-enabled mobile phone.
LAN Access Profile (LAP): Defines how a Bluetooth-enabled device can connect to a computer network.
Generic Object Exchange Profile (GOEP): Defines a set of protocols that applications use for exchanging objects.
Object Push Profile (OPP): OPP is used to send and receive objects and files between Bluetooth devices. OPP typically only supports certain types of objects—commonly this includes electronic business cards and media like photos, wallpaper and ringtones. It is called “Push” because the sender initiates the communication with the intention of “pushing” a file to the receiver. This is different a “pull” system like a Web browser where the receiver (you and the browser) “pull” or request a file from the sender (Web server).
File Transfer Profile (FTP): This profile works together with the GOEP and is another way to transfer files between two Bluetooth devices.
Synchronization Profile (SP): This works like Microsoft ActiveSync—it is used together with GOEP to synchronize calendar and address information between two Bluetooth devices, such as a laptop and mobile phone.
There are a couple of other commonly used profiles:
- Hands-Free Profile (HFP): HFP allows you to talk on your Bluetooth mobile from inside your car, leaving your hands free to operate the car (where it is legal to do so, of course). HFP requires a hands-free kit or cradle inside the car to provide a different speaker and microphone to conduct the conversation through instead of using the phones speaker and microphone. It is also possible to get specialized car stereos that have this built in.
- Advanced Audio Distribution Profile (A2DP) and Audio Video Remote Control Profile (AVRCP): These profiles usually work together in Bluetooth wireless stereo headphones. The A2DP profile provides higher quality sound than the Headset Profile as well as providing stereo sound instead of mono sound.
New profiles have been developed and others are in the works, but the above list covers the major profiles. Actually, at this point in time, the average consumer will get by with awareness of only a few of them: Headset, Object Push, and Hands-Free. As more Bluetooth products and applications are released, other profiles will come into popular use as driven by the consumer market.
