Bluetooth can be used for a variety of applications. Most applications have a server and a client side. A client usually establishes the Bluetooth connection to the master and requests the transfer of some kind of data. Thus, the master and the client sides of a Bluetooth service are separate. For example, the client side establishes a connection with the server to transfer a Virtual Contact File (VCF) entry from one device to another. The client then transfers the VCF entry as the sending component.

On the other hand, the server accepts the VCF entry as receiving element. To ensure that the client can communicate with servers implemented by different manufacturers, the standard defines several Bluetooth profiles. For each application (headset, file transfer, audio streaming, basic printing, etc.), an individual Bluetooth profile has been defined, which describes how the server side and the client side communicate with each other. If both sides support the same profile, interoperability is ensured.

It is worth noting that the client/server principle of the Bluetooth profile should not be confused with the master/slave concept of the lower Bluetooth protocol layers. The master/slave concept is used to control piconet, i.e., who is allowed to send and at what time, while the client/server policy describes a service and a user of a service. It is irrelevant whether the Bluetooth device used as a server for a particular service is the master or the slave in the piconet. A number of different Bluetooth profiles for a wide range of services are given below:

• Advanced audio distribution profile: Profile for the transmission of high-quality audio, for example, music between an MP-3 player and a Bluetooth headset.
• Audio/video remote control profile: Profile to control audio/video devices remotely. This profile can be used, for example, with the advanced audio distribution profile to remotely control the audio player from the headset or an independent remote control.
• Basic imaging profile: Transfer of pictures from and to digital cameras.
• Basic printing profile: Printing profile for mobile devices such as mobile phones to enable them to print information without a printer driver.
• Common ISDN access profile: Profile for interconnecting an ISDN adapter with a remote device such as a PC or notebook.
• Dial-up networking (DUN) profile: Bluetooth connection between a modem or a mobile phone and a remote device such as a PC or a notebook.
• FAX profile: Profile for FAX transmissions.
• File transfer profile: This profile can be used to exchange files between two Bluetooth devices.
• Hands-free profile: This profile is used to connect mobile phones with hands-free sets in cars.
• Hard copy cable replacement profile: Cable replacement between printers and a remote device such as a PC.
• Headset profile: Profile for wireless headsets used with mobile phones. Voice quality transmissions only, not suitable for music.
• Human interface device (HID) profile: Connects mouse(s), keyboard(s), and joystick(s) to PCs, notebooks, and smartphones.
• LAN access profile: IP connection between a smartphone, PC, or notebook with a LAN and the Internet.
• Object push profile: Simple exchange of calendar entries, address book entries, etc.; used for ad hoc transfers.
• Personal area network (PAN) profile: Same as the LAN access profile. However, the PAN profile does not simulate an Ethernet network card but instead uses Bluetooth protocols for this purpose.
• SIM access profile: Provides access for hands-free equipment in cars to the data stored on the SIM card of a mobile phone.
• Synchronization profile: Synchronization of personal information manager (PIM) applications for calendar and address book entries, notes, etc.