Before data can be exchanged between two Bluetooth devices, the devices are usually required to authenticate each other. To exchange single files, such as images or business cards, the recipient is usually asked to accept or reject the information.
When the task is too complex to manually accept or reject each piece of information, such as when using a headset or synchronising calendar and contact information with your PC, the authentication process must be completed beforehand. This establishes a permanent trusted relationship between the two devices: pairing.