Bluetooth

When you use computers, entertainment systems or telephones, the various pieces and parts of the systems make up a community of electronic devices. These devices communicate with each other using a variety of wires, cables, radio signals and infrared light beams, and an even greater variety of connectors, plugs and protocols.

A Bluetooth connection is wireless and automatic, and it has a number of interesting features that can simplify our daily lives.

Bluetooth is an industrial specification for wireless personal area networks (PANs). Bluetooth provides a way to connect and exchange information between devices such as mobile phones, laptops, personal computers, printers, digital cameras, and video game consoles over a secure, globally unlicensed short-range radio frequency.

Uses

Bluetooth is a standard and communications protocol primarily designed for low power consumption, with a short range (power-class-dependent: 1 meter, 10 meters, 100 meters) based on low-cost transceiver microchips in each device.

Bluetooth enables these devices to communicate with each other when they are in range. The devices use a radio communications system, so they do not have to be in line of sight of each other, and can even be in other rooms, as long as the received transmission is powerful enough.

Applications

More prevalent applications of Bluetooth include:

  • Wireless control of and communication between a mobile phone and a hands-free headset. This was one of the earliest applications to become popular.
  • Wireless networking between PCs in a confined space and where little bandwidth is required.
  • Wireless communications with PC input and output devices, the most common being the mouse, keyboard and printer.
  • Transfer of files between devices with OBEX.
  • Transfer of contact details, calendar appointments, and reminders between devices with OBEX.
  • Replacement of traditional wired serial communications in test equipment, GPS receivers, medical equipment, bar code scanners, and traffic control devices.
  • For controls where infrared was traditionally used.
  • Sending small advertisements from Bluetooth enabled advertising hoardings to other, discoverable, Bluetooth devices.
  • Two seventh-generation game consoles, Nintendo’s Wii and Sony’s PlayStation 3 use Bluetooth for their respective wireless controllers.
  • Dial-up internet access on personal computer or PDA using a data-capable mobile phone as a modem.

How Bluetooth Operates?

Bluetooth networking transmits data via low-power radio waves. It communicates on a frequency of 2.45 gigahertz (actually between 2.402 GHz and 2.480 GHz, to be exact). This frequency band has been set aside by international agreement for the use of industrial, scientific and medical devices (ISM).

A number of devices that you may already use take advantage of this same radio-frequency band. Making sure that Bluetooth and these other devices don’t interfere with one another has been a crucial part of the design process.

Bluetooth can connect up to eight devices simultaneously. With all of those devices in the same 10-meter (32-foot) radius, you might think they’d interfere with one another, but it’s unlikely. Bluetooth uses a technique called spread-spectrum frequency hopping that makes it rare for more than one device to be transmitting on the same frequency at the same time.

Sources: Electronics How stuff works

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