Your wireless earbuds connect to your phone without a cable. That is Bluetooth — a short-range wireless technology for connecting devices. It uses radio waves in the 2.4 GHz band to exchange data over distances of about 10 meters. It is designed for low power, which is why it works in tiny earbuds and fitness trackers.

Bluetooth was invented in 1994 by Ericsson, a Swedish telecom company. The name comes from a 10th-century Danish king, Harald Bluetooth, who united warring tribes. The technology does something similar: it lets devices from different makers talk to each other.

Common uses

• Audio: headphones, speakers, car systems
• Peripherals: keyboards, mice, game controllers
• Health: heart rate monitors, glucose meters
• Smart home: locks, lights, thermometers

Bluetooth has evolved. Classic Bluetooth handles streaming audio. Bluetooth Low Energy (BLE) handles small bursts of data for sensors and beacons. BLE is what lets a tile tracker run for a year on a coin cell.