What Is Bluetooth? The Ultimate Guide
Former Lifewire writer Melanie Uy has 5+ years’ experience writing about consumer-oriented technology and is an expert telecommuter.
Ryan Perian is a certified IT specialist who holds numerous IT certifications and has 12+ years’ experience working in the IT industry support and management positions.
In This Article
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
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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.
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.
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.
Bluetooth powers smart speakers such as the Amazon Echo and Google Home devices and wireless portable speakers designed for indoor, outdoor, and beach use.
Bluetooth Technology Overview
One key reason for the incredible success of Bluetooth ® technology is the tremendous flexibility it provides developers. Offering two radio options, Bluetooth technology provides developers with a versatile set of full-stack, fit-for-purpose solutions to meet the ever-expanding needs for wireless connectivity.
Whether a product streams high-quality audio between a smartphone and speaker, transfers data between a tablet and medical device, or sends messages between thousands of nodes in a building automation solution, the Bluetooth Low Energy (LE) and Bluetooth Classic radios are designed to meet the unique needs of developers worldwide.
The Bluetooth Classic radio, also referred to as Bluetooth Basic Rate/Enhanced Data Rate (BR/EDR), is a low power radio that streams data over 79 channels in the 2.4GHz unlicensed industrial, scientific, and medical (ISM) frequency band. Supporting point-to-point device communication, Bluetooth Classic is mainly used to enable wireless audio streaming and has become the standard radio protocol behind wireless speakers, headphones, and in-car entertainment systems. The Bluetooth Classic radio also enables data transfer applications, including mobile printing.
The Bluetooth Low Energy (LE) radio is designed for very low power operation. Transmitting data over 40 channels in the 2.4GHz unlicensed ISM frequency band, the Bluetooth LE radio provides developers a tremendous amount of flexibility to build products that meet the unique connectivity requirements of their market. Bluetooth LE supports multiple communication topologies, expanding from point-to-point to broadcast and, most recently, mesh, enabling Bluetooth technology to support the creation of reliable, large-scale device networks. While initially known for its device communications capabilities, Bluetooth LE is now also widely used as a device positioning technology to address the increasing demand for high accuracy indoor location services. Bluetooth LE now includes features that enable one device to determine the presence, distance, and direction of another device.
LE 2M PHY: ≤-70 dBm
LE 1M PHY: ≤-70 dBm
LE Coded PHY (S=2): ≤-75 dBm
LE Coded PHY (S=8): ≤-82 dBm
Asynchronous Connection-oriented
Isochronous Connection-oriented
Asynchronous Connectionless
Synchronous Connectionless
Isochronous Connectionless
* Devices shall not exceed the maximum allowed transmit power levels set by the regulatory bodies that have jurisdiction over the locales in which the device is to be sold or intended to operate. Implementers should be aware that the maximum transmit power level permitted under a given set of regulations might not be the same for all modulation modes.