What is Bluetooth?

Danny Rawles
Bluetooth logo

Bluetooth is simply a wireless technology that allows secure data communication between two devices over short distances (short meaning meters rather than miles).

Bluetooth data communication can be anything from sending files to printing documents.

Although Bluetooth is available on a wide variety of devices, you're probably most familiar with it because of your mobile phone. Bluetooth's popularity and adoption has without doubt exploded due to the mobile phone industry.

The beauty of Bluetooth is its universal compatibility. This means that absolutely any Bluetooth device can connect to any other with ease.

Bluetooth name

The somewhat odd name probably confuses many since it doesn't attempt to describe what it is or what it does. It certainly doesn't sound very techy so you'd be forgiven for thinking it might be something to do with dental hygiene.

In fact the name comes from the tenth-century Danish King, Harald Bluetooth and was chosen because one of the developers was reading a book about Vikings at the time which told how King Harald helped to unite warring factions. Bluetooth helps unite otherwise incompatible devices!

How does Bluetooth work?

Radio wave - frequency. Blue wave on a black background

Bluetooth uses radio waves to send and receive data which is the same principle as TV and FM radio but on a much smaller scale. You can think of it like talking. The person talking is the transmitter and is "wirelessly" sending sound waves to another person's ears, the receiver.

Talking also has a limited range - shouting will of course increase the range and is the equivalent of turning the power up on a radio transmitter.

As well as using radio waves, Bluetooth creates a secure mini-wireless network that devices can communicate on.

Devices first need to be connected or "paired" which will usually involve authenticating via a pin or passcode. Once paired, data can either be sent or received from one device to another.

What is Bluetooth used for?

Bluetooth is actually used for many different things from sending and receiving files (pictures, documents etc.) to streaming music.

For example if you have some pictures you've taken on your phone and you want to send them to someone else's phone you can do this over Bluetooth.

You don't have to worry about finding the right cables or software and importantly it has nothing to do with the internet so you don't have to worry about being connected to the web or using any data allowance.

Other uses of Bluetooth are

  • Wirelessly transferring files between phones, computers and laptops
  • Wireless hands-free phone calls between your mobile phone and a Bluetooth headset
  • Wireless music streaming between your mobile phone/tablet and a Bluetooth speaker
  • Wireless mouse & keyboard
  • Wireless gaming between your controllers and the console (e.g. the PlayStation 4 uses Bluetooth controllers)
  • Wireless syncing between a smartwatch and smartphone
  • Wireless health and fitness gadgets that sync to your smartphone
  • Wireless printing

Bluetooth range

Bluetooth is designed to work over short distances however the range depends on the class of radio transmitter that is used.

  • Bluetooth has a maximum range of up to 100 meters, although devices with this kind of range are usually used in industrial hardware and use Class 1 Radios.
  • More commonly a range of up to 10 meters is achievable in most consumer devices such as mobile phones and computers. These use Class 2 Radios.
  • There are also Class 3 radios which have a range of up to 1 meter although not many devices these days use Class 3 radios since the range is so limited.

How to use Bluetooth

Using Bluetooth is fairly straight forward and consists of two main steps

  1. Pairing two devices together
  2. Sharing or transferring data

Most devices will have a Bluetooth menu that will allow you to either search or broadcast.

To pair your device with another device, one of them has to broadcast a signal and the other has to search for it.

Once a connection is made, you'll usually need to enter a passcode to make sure the connection is secure. The passcode is either provided to you or something you make up and enter on both devices.

You only have to pair devices once – next time you want to connect, simply make sure you're in range and Bluetooth is turned on and the devices will connect automatically.

The second step is to send, share or receive data. Using the Bluetooth menu again will usually give you options to send files via Bluetooth. Selecting this option will allow you to browse for the files you want to send and who you want to send them to.

What is Bluetooth in a car?

You may have heard or read about cars that have Bluetooth. Well what is this actually referring to?

This will usually mean the stereo or in-car entertainment system has Bluetooth built-in which allows you to connect your mobile phone to your car so you can make and receive hands-free phone calls.

Since it's illegal to drive and use a hand-held mobile phone in the UK (and many other countries), having a built-in hands-free system is not only cool and makes your friends jealous but helps keep you safe and on the right side of the law!

When on a call the audio is usually sent through your car's speakers. There will be a microphone installed somewhere close to the driver's position which basically means your phone can stay firmly in your pocket or bag.

More advanced in-car Bluetooth systems

  • Allow you to transfer your phonebook to the car
  • Show you who is calling on a display screen
  • Display or even read out text messages
  • Use voice commands to make calls or send messages
  • Pause any music you were listening to

Advantages of Bluetooth

  • Probably the biggest advantage of Bluetooth is its compatibility. Practically any make and model of device can connect to any other.
  • It's designed to be super low-powered. When in use is only uses tiny amounts of power making it ideal for battery powered devices.
  • Bluetooth reduces interference by cleverly changing its signal if it detects other radio signals using the same frequency. This means greater overall performance and reduces the chance of lost data or broken connections
  • Bluetooth doesn't require line of sight and can work through walls

Disadvantages of Bluetooth

  • The speed at which data can be transferred is about 2 Megabits per second (Mb/s) or about 0.25 Megabytes per second (MB/s) so it isn't really ideal for transferring large files. A few pictures here and there wouldn't take too long but large music files or even larger video files would take several minutes.
  • Bluetooth might be low-powered but when enabled in a portable device such as a mobile phone or tablet, the battery is being continually drained. In fact it's often a power-saving tip to turn such features off when not in use to conserve power. So it's not always the most convenient feature to use if you have to remember to always turn it on and off.
  • Although it's designed to be short-range, 10 meters could be limiting for some uses especially when outdoors.

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