Bluetooth (Bluetooth?): is a wireless technology standard that enables short-range data exchange (using UHF radio waves in the ISM band at 2.4-2.485GHz) between fixed devices, mobile devices and building personal area networks. Bluetooth technology was originally created by telecom giant Ericsson in 1994 as an alternative to the RS232 data line. Bluetooth allows multiple devices to be connected, overcoming the challenges of data synchronization.
Bluetooth is a standard wireless communication protocol based on a device's low-cost transceiver chip with a close transmission range and low power consumption.
As devices use radio (broadcast) communication systems;
not connected by physically visible wires, however a quasi-optical wireless path must be feasible. The range is power and category dependent, but the effective range varies in practice.