How it began
The origins of Bluetooth go back to 1989 and to Ericsson's research lab in Lund. Nils Rydbeck, chief technology officer of Ericsson Mobile, and the Swedish physician and inventor Johan Ullman were looking for marketable alternatives to a wired connection. Rydbeck asked Tord Wingren to specify the technology and build a team. Wingren commissioned two engineers, Jaap Haartsen, who is Dutch, and Sven Mattisson, who is Swedish, and from 1994 they designed a workable short-range radio link. At the time, devices such as computers and headsets were connected by cables, and the two engineers set out to replace the RS-232 serial cable standard.
How it works
Bluetooth devices form small networks called piconets and exchange data by radio in the 2.4 GHz band. A central device such as a phone sends data to or requests data from peripherals such as headsets, which do not talk to each other. The signal hops between frequencies, which makes it resistant to interference and hard to intercept. Devices connect in three stages: inquiry, in which they discover each other, paging, in which they form a connection, and the connection itself. Paired devices remember each other and reconnect when in range.
How it spread
The technology is named after a 10th-century Viking king, Harald Bluetooth, and a stone bearing his name stands outside the Ericsson building in Lund. The first widely available consumer device with Bluetooth, Ericsson's T39 phone, reached the mass market in 2001. Haartsen's work earned him a nomination for the European Inventor Award of the European Patent Office.
Where it stands today
Range has grown from about 10 meters in the first generation to as much as 240 meters in the fifth, and Bluetooth Low Energy has cut power use. The technology now carries high-quality audio, has prompted phone makers to drop the 3.5 mm headphone jack, and is widely used in connected devices. Ericsson cited an estimate that shipments of Bluetooth devices would reach seven billion by 2026.
