What Is Bluetooth? The Ultimate Guide

What Bluetooth is, what it does, and how it works

Bluetooth is a short-range wireless communication technology that allows devices such as mobile phones, computers, and peripherals to transmit data or voice wirelessly over a short distance. The purpose of Bluetooth is to replace the cables that normally connect devices, while still keeping the communications between them secure.

The "Bluetooth" name is taken from a 10th-century Danish king named Harald Bluetooth, who was said to unite disparate, warring regional factions. Like its namesake, Bluetooth technology brings together a broad range of devices across many different industries through a unifying communication standard. 

Bluetooth Technology

Google glass being worn by a man in a open office setting
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Developed in 1994, Bluetooth was intended as a wireless replacement for cables. It uses the same 2.4GHz frequency as some other wireless technologies in the home or office, such as cordless phones and WiFi routers. It creates a 10-meter (33-foot) radius wireless network, called a personal area network (PAN) or piconet, which can network between two and eight devices. This short-range network allows you to send a page to your printer in another room, for example, without having to run an unsightly cable.

Bluetooth uses less power and costs less to implement than Wi-Fi. Its lower power also makes it far less prone to suffering from or causing interference with other wireless devices in the same 2.4GHz radio band. 

Bluetooth range and transmission speeds are typically lower than Wi-Fi (the wireless local area network that you may have in your home). Bluetooth v3.0 + HS — Bluetooth high-speed technology — devices can deliver up to 24 Mbps of data, which is faster than the 802.11b WiFi standard, but slower than wireless-a or wireless-g standards. As technology has evolved, however, Bluetooth speeds have increased.

The Bluetooth 4.0 specification was officially adopted on July 6, 2010. Bluetooth version 4.0 features include low energy consumption, low cost, multivendor interoperability, and enhanced range. 

The hallmark feature enhancement to the Bluetooth 4.0 spec is its lower power requirements; devices using Bluetooth v4.0 are optimized for low battery operation and can run off of small coin-cell batteries, opening up new opportunities for wireless technology. Instead of fearing that leaving Bluetooth on will drain your cell phone's battery, for example, you can leave a Bluetooth v4.0 mobile phone connected all the time to your other Bluetooth accessories. 

Connecting With Bluetooth

Many mobile devices have Bluetooth radios embedded in them. PCs and some other devices that do not have built-in radios can be Bluetooth-enabled by adding a Bluetooth dongle, for example.

The process of connecting two Bluetooth devices is called "pairing." Generally, devices broadcast their presence to one another, and the user selects the Bluetooth device they want to connect to when its name or ID appears on their device. As Bluetooth-enabled devices proliferate, it becomes important that you know when and to which device you're connecting, so there may be a code to enter that helps ensure you're connecting to the correct device.

This pairing process can vary depending on the devices involved. For example, connecting a Bluetooth device to your iPad can involve different steps from those to pair a Bluetooth device to your car.

Bluetooth Limitations

There are some downsides to Bluetooth. The first is that it can be a drain on battery power for mobile wireless devices like smartphones, though as the technology (and battery technology) has improved, this problem is less significant than it used to be.

Also, the range is fairly limited, usually extending only about 30 feet, and as with all wireless technologies, obstacles such as walls, floors, or ceilings can reduce this range further.

The pairing process may also be difficult, often depending on the devices involved, the manufacturers, and other factors that all can result in frustration when attempting to connect.

How Secure Is Bluetooth?

Bluetooth is considered a reasonably secure wireless technology when used with precautions. Connections are encrypted, preventing casual eavesdropping from other devices nearby. Bluetooth devices also shift radio frequencies often while paired, which prevents an easy invasion.

Devices also offer a variety of settings that allow the user to limit Bluetooth connections. The device-level security of "trusting" a Bluetooth device restricts connections to only that specific device. With service-level security settings, you can also restrict the kinds of activities your device is permitted to engage in while on a Bluetooth connection. 

As with any wireless technology, however, there is always some security risk involved. Hackers have devised a variety of malicious attacks that use Bluetooth networking. For example, "bluesnarfing" refers to a hacker gaining authorized access to information on a device through Bluetooth; "bluebugging" is when an attacker takes over your mobile phone and all its functions.  

For the average person, Bluetooth doesn't present a grave security risk when used with safety in mind (e.g., not connecting to unknown Bluetooth devices). For maximum security, while in public and not using Bluetooth, you can disable it completely.

  • What is Bluetooth 5.0?

    Bluetooth 5.0 is the newest version of the wireless standard. Devices began supporting Bluetooth in mid-2017, and it's now implemented in many compatible Bluetooth devices. Bluetooth 5.0 offers four times the range, twice the speed, and improved bandwidth over Bluetooth 4.0.

  • What is Bluetooth tethering?

    Bluetooth tethering is when Bluetooth pairs two devices in the same Personal Area Network (PAN), and the internet connection of one device can be shared with the second device.

  • What is a Bluetooth speaker?

    Bluetooth powers smart speakers such as the Amazon Echo and Google Home devices and wireless portable speakers designed for indoor, outdoor, and beach use.

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