How to Pair Two Bluetooth Devices?

Pairing (also known as bonding) is a process of exchanging passkeys (a.k.a. PIN codes) between two Bluetooth devices to identify each other. After two Bluetooth devices have been paired, they are able to encrypt data before being transmitted. In most cases, pairing should be done before two Bluetooth devices start a connection. A paired device is not removed when the device is turned off or comes out of discoverable mode.
In this example, we are going to pair a PC running Windows XP SP2 with a Bluetooth mobile phone. The following procedures generally apply to any mobile phone, old and new generation of phones, and smartphones that support the standard Bluetooth technology such as the Nokia Windows phone. Consult your phone guide for more detailed procedures to respond to a connection request or start a new connection in the pairing process. Usually, you need to do only a few steps which are very intuitive, i.e. pressing a button or typing on an input box.

1. Attach a Bluetooth dongle (adapter) to a port on your computer (typically a USB port). If this is your first use of the dongle, then there will be a very quick Bluetooth device recognition and installation process. As a result, your adapter will be working using Windows XP SP2 Generic Bluetooth Radio driver.
Skip this step if your computer has a built-in Bluetooth transceiver.
2. From the Bluetooth icon that appears on the taskbar (or from Control Panel), open Bluetooth Devices window.
3. On Options tab, select "Turn discovery on" so other Bluetooth devices in the vicinity will see it.
4. Assign a name for your computer (optional). You can do this by right-clicking My Computer icon on the desktop, then on System Properties window, select Computer Name tab. Click "Change".
5. Turn on your mobile phone.
6. Go to the connectivity menu in your mobile phone. Activate its Bluetooth radio. Then make your mobile phone discoverable.
7. Assign a name (optional). If you don't give it a name, it will usually be identified by its brand and series.
8. Open Bluetooth Devices window.
9. On Devices tab, click Add. This will open the Add Bluetooth Device Wizard.
10. Select the "My device is set up and ready to be found" checkbox, and then click Next.
11. The wizard will search for discoverable Bluetooth devices. Your mobile phone must be on the list of discoverable devices. Select your mobile phone and then click Next.

Pairing Bluetooth devices on Windows XP SP2

Picture: Authorization by exchanging a passkey.

12. Follow the instructions to input a passkey manually or let Windows set a passkey automatically.
13. Check your mobile phone screen, there must be a message from your computer asking your mobile phone to input a passkey.
14. When the same passkeys have been entered on both sides, your computer and mobile phone are paired and ready to start any available Bluetooth services.

More pairing screenshots can be found on this page.

The above procedures apply if your computer initiates the pairing. The pairing can also be initiated by your mobile phone. Follow the instructions in your mobile phone to set it discoverable and to discover other Bluetooth devices in its surrounding. In the discovered devices list, select the Bluetooth-enabled computer name that you want to connect to, and provide a passkey when prompted.

A message balloon requesting a Bluetooth connection

Picture: A balloon appears from the Bluetooth icon
when another device requests a connection.

A balloon will appear on the Bluetooth taskbar icon with a message telling you that another Bluetooth device requests a connection to your computer. Click the balloon, and input the same passkey on your computer when prompted.