Bluetooth

Bluetooth is a radio standard used to transmit data between nearby devices without cables. It operates at a frequency near 2.4 GHz, which is part of the ISM band available licence-free in most of the world. The typical range for handheld devices is up to ten meters, though high-power equipment can reach greater distances.

Bluetooth is found in modern mobile phones, headsets, keyboards, vehicles, and medical devices. The standard is managed by the Bluetooth Special Interest Group (SIG), an association of technology companies that determines new specifications.

History and name

Development began in the 1980s, led by the Swedish company Ericsson. The name 'Bluetooth' comes from Harald Bluetooth, a medieval Danish king said to have united disparate tribes—used as an analogy for the goal of connecting different devices. The logo is based on runic letters representing the king's name.

How it works

Bluetooth uses a method called frequency hopping, in which the radio rapidly switches among many channels. This reduces interference from other devices using the same band, such as Wi-Fi networks. When two devices connect, they perform pairing, exchanging secret keys to secure the data.

Versions and development

Bluetooth divides into two main categories: Bluetooth Classic, suited for continuous data such as voice and music, and Bluetooth Low Energy (BLE), designed for small devices that use little power, such as fitness trackers and smartwatches. Newer versions have increased range, speed, and the ability to connect many devices simultaneously.

Security

Because data is transmitted over the air, there is a risk that a third party may eavesdrop or attempt to establish an unauthorized connection. Newer standards use encryption and authentication methods to reduce this risk. Users are advised to disable Bluetooth when not in use and to reject pairing requests from unknown devices.