How Does Bluetooth Pairing Work?

By Mike Munson

Bluetooth Pairing

Bluetooth pairing is necessary whenever two Bluetooth devices connect to each other to share resources. A trusted relationship is established between the devices using a numerical password, commonly referred to as a passkey. Depending on how often one Bluetooth device connects to another, the user might opt to have the passkey saved for future connection attempts or prompt to enter the passkey each time the devices request communication with each other.

Bluetooth Pairing Service

In most cases, Bluetooth devices are paired only once, and the details of the relationship are saved for later connections. The pairing service, an integral component of all Bluetooth devices, is responsible for maintaining a list of devices that have made successful connections in the past. It is essentially a passkey manager remembers the specific details for other trusted Bluetooth devices. If a user has a reason not to allow automatic connections for specific devices, the Bluetooth pairing service will not store passkey details.

Preparing to Pair

Because Bluetooth is a standardized-communication method, making trusted connections between Bluetooth devices is a straight-forward and simple process. Before attempting to pair two Bluetooth devices for the first time, it is recommended to have both devices fully charged, turned on and Bluetooth enabled. At least one of the devices must be set to discoverable mode, which means for a short period, the device will be announcing its presence to other devices within its range.

Pairing Bluetooth Devices

Have the second device search for other Bluetooth devices. There are many types of devices on the market and just as many ways to put your device into discoverable or searching modes. It is recommended you view the documentation for your specific devices to determine how to enter these modes. Within 30 seconds, you should see the devices have found each other and a prompt to enter a passkey will be presented.

Bluetooth Pairing Passkey

The passkey is a four-digit number you supply at the time you are establishing your trusted relationship between devices. If a specific passkey is set by the manufacturer, you can try "0000," or you might have to find the passkey in your device's documentation and enter that instead. After you enter a passkey, the other device might prompt you to enter the passkey you entered. When the passkey is verified on the other device, the two have been paired. The Bluetooth device and passkey information are stored using the pairing service so future pairing attempts do not have to be made unless desired as a security precaution.