Bluetooth

Bluetooth  is an open wireless technology standard used for exchanging data over a short distance, ranging from around an arms length from each other to over 100m, and can be used from fixed and mobile devices, most mobile phones commonly come with Bluetooth nowadays.
Bluetooth was first implemented in 1994, originally as a wireless alternative to RS-232 data cables.
It uses radio technology called frequency-hopping spread spectrum and it chops up data being sent and transmits chunks of it.
Bluetooth is used in wireless headsets for phones and wireless networking between computers where little bandwidth is required, as well as many other things.
There have been 4 versions of Bluetooth since '94, each building on it's predecessor to a faster data transfer standard.