Learn in the textbookSerial and Short-Range Wireless Interfaces
DefinitionBluetooth is a short-range wireless standard that uses radio waves (電波) to link devices without cables, typically within a few meters up to about 10 m.
ExplanationIt runs on the 2.4 GHz band and draws little power, so it suits small battery-powered gadgets. After an initial pairing (ペアリング) step registers the other device, the two reconnect automatically from then on.
AnalogyThink of a walkie-talkie that only talks to the partners it has been set up with, as long as they are nearby.
Memory hookThe name comes from "Bluetooth", the nickname of Harald I, the 10th-century Danish king who united Denmark and Norway, reflecting the aim of uniting many kinds of devices.