The WIRED Guide to Bluetooth

Almost everyone uses Bluetooth every daybut what is it exactly? Bluetooth is a ubiquitous wireless connectivity standard that connects our headphonesspeakerssmartwatchesand smart rings with our phones; headsetskeyboardsand mice with our laptops; and can even be used to broadcast audio to individuals or large audiences in public places with Auracast.

In this Bluetooth guideI'll briefly explain how it worksreview its two-decade history to describe the differences between versionsand examine what’s next for the standard.

How Does Bluetooth Work?

Bluetooth enables supported devices to connect wirelessly using high-frequency radio waves. Bluetooth relies on the same 2.4-GHz frequency band as 2.4-GHz Wi-Fi butthanks to adaptive frequency-hopping (AFH)it avoids crowded frequencies and limits interference. Bluetooth also uses lower powerhas less rangeand isn't as fast as 2.4-GHz Wi-Fi.

Bluetooth has had its share of vulnerabilitiesbut it’s not too difficult to stay secureand the latest versions are far more secure by design. Everyone has encountered Bluetooth pairing problems and annoying glitches—we have a guide to help you fix Bluetooth issues—but it's a robust standard that remains enormously convenient andconsequentlyhugely popular. Every version of Bluetooth is backward compatiblemeaning a Bluetooth 5.3 device can connect to a Bluetooth 4.0 device. But the features and functionality are always limited by the older device.

Companies employ Bluetooth in many proprietary featureslike Apple’s AirDrop and Google’s Quick Share. While the U1 chip in Apple devices enables ultra-wideband (UWB) technology to determine the direction of your phone and help you share files with nearby devicesAirDrop uses Bluetooth for the initial discovery process and then switches to Wi-Fi to transmit files. Google merged Nearby Share with Samsung’s Quick Share in 2024and much like AirDropit uses Bluetooth to establish a connection and then Wi-Fi to transfer files.

These are just two examples. Google also has a standard called Fast Pair that quickly connects a wireless device with a smartphoneand it uses Bluetooth too.

History of Bluetooth

Bluetooth is named after King Harald “Bluetooth” Gormsson—the logo is a combination of his runes for his initials—who had a literal blue tooth (it was dead). He united Denmark and Norway in 958. This short-range radio technology grew from a 1996 meeting between IntelEricssonand Nokia. The first version didn’t land until 1999but Bluetooth didn’t take off until a few years later.

The standard is managed by a not-for-profit Bluetooth Special Interest Groupor Bluetooth SIGand it's headquartered in the US. While there are thousands of membersthe most influential companies help shape the direction of the standard and include companies like EricssonIntelNokiaAppleMicrosoftLenovoand Google.

Every version brought myriad incremental improvements to make Bluetooth fastermore efficientmore secureand less buggybut we’re just going to run through the headline features here.

• Bluetooth 1.2 in 2003 figured out how to avoid Wi-Fi interference and enabled quicker pairinghelping to popularize the standard.
• Bluetooth 2.0 in 2004 brought EDR (Enhanced Data Rate)tripling the data rate from 1 to 3 Mbps.
• Bluetooth 2.1 in 2007 brought SSP (Secure Simple Pairing)enhancing security and reducing power draw.
• Bluetooth 3.0 + HS (High Speed) in 2009 bumped rates up by initially connecting via Bluetooth and then switching to Wi-Fi.
• Bluetooth 4.0 LE (Low Energy) landed in 2010 andas the name suggestsreduced power requirements even further.
• Bluetooth 4.1 in 2013 allowed Bluetooth devices to communicate with each other.
• Bluetooth 4.2 boosted data rates and IoT connectivity in 2014.
• Bluetooth 5 in 2016 increased the potential range massivelygoing from around 50 meters to well over 200 meters. But range is dependent on the power classand there are three classes. Class 1 devices have the greatest range and use the most powerClass 2 are limited to around 10 metersand Class 3 is only 1 meter.
• Bluetooth 5.1 in 2019 brought faster pairing and better tracking accuracy.
• Bluetooth 5.2 in 2020 allowed for multiple simultaneous data streams and better control over the power and signal required by connected devices.
• Bluetooth 5.3 in 2021 brought improvements in audio qualityincreased power efficiencyand wider compatibility.
• Bluetooth 5.4 in 2023 improved security and reduced latencybut it also included functionality aimed at retailersallowing them to monitor and change electronic shelf labels (ESL). Devices that support ESL are expected to ship in 2027.
• Bluetooth 6.0 is the latest versionannounced in 2024. It includes a precise tracking capability called Channel Sounding that enables two devices to accurately measure the distance between themalongside various efficiency improvements.

How to Use Bluetooth

One of the main reasons Bluetooth is so popular is because it's easy to use. You can generally turn Bluetooth on via the settings of your phone or computer and find a menu of available devices to connect with. Sometimes you need to put the device you want to connect with into pairing modewhich may involve holding down a button (refer to the device manufacturer). There's usually a pairing pop-up on one or both devices so you can accept the connection.

Bluetooth support is built into the chipsets of many devicesbut if your computer or laptop lacks ityou can always add it via a donglelike this Asus Bluetooth 5.0 Adapter ($18) or this one from Plugable ($17). If range is an issuethis popular Techkey Bluetooth 5.3 Adapter ($22) includes an antenna to boost it.

You can also add Bluetooth functionality to headphonesspeakersor car stereos that lack it with something like the 1Mii Bluetooth 5.3 Music Receiver ($17)but the device must have a 3.5-mm port or jack. We have also tested and like Scosche's Bluetooth Radio Transmitter for cars ($30)which adds Bluetooth connectivity to vehicles without it through the cigarette lighter port.

What’s Next for Bluetooth?

The most exciting new feature on the horizon for Bluetooth is Auracast. Announced by the Bluetooth (SIG) in 2022the idea is that you will be able to broadcast and join audio streams in public places by selecting a stream from a list (as you currently do to join a Wi-Fi network)by scanning a QR codeor by tapping where you see an Auracast logo.

Auracast will allow several people to connect to the same audio stream simultaneously and could be used to watch a movie together on a smartphone in the back of the carget audio from TVs in public spaces like the gymor enhance accessibility for the deaf and hard of hearing who could stream audio directly to their hearing aids at a public concert.

The catch is that devices must support Bluetooth 5.2 or later and the Public Broadcast Profile (PBP) to receive Auracast streams. It will likely take a while for devices with transmitter capabilities to roll outthough we may see plug-ins to enable this in the short term. Venue adoption is another piece of the puzzleas they will have to deploy Auracast broadcast transmittersso it may be a few years before this is widely available.

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