What Is Bluetooth?

Learn which Bluetooth features are essential to you and build an understanding of the Bluetooth technology.

A Bluetooth keyboard, controller, and headset, and a Bluetooth adapter Brandon Jones / TechReviewer

Last Updated: September 10, 2021

Written by Kevin Jones

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What Is Bluetooth?

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Bluetooth is a short-range wireless technology used to transmit audio, control devices, and transfer small amounts of data up to about 33 feet (10 meters) for Class 2 Bluetooth devices.

Bluetooth is often used to connect headphones, keyboards, game controllers, mice, microphones, and other devices with PCs, laptops, and mobile devices such as phones, tablets, and watches.

Bluetooth is used to:

  • Replace cables
  • Shares files between devices
  • Sync data between devices (such as phone contacts)
  • Share Internet access between devices

Why Was Bluetooth Created?

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Bluetooth was first introduced to connect phones to other devices without using cables; it was a wireless alternative to the wired RS-232 interface. Bluetooth would allow phones to wirelessly connect to computers, headsets, and car audio systems.

What Is a Piconet?

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A Bluetooth network is called a piconet. In a piconet, one host device can connect to up to seven client devices. The maximum device limit depends on the implementation.

What Device Is Needed to Connect a Computer to a Bluetooth Device?

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If your computer includes built-in support for Bluetooth, you can use that to connect to a Bluetooth device. Built-in Bluetooth is more commonly available on laptops.

Otherwise, you can use a USB Bluetooth adapter to connect your computer to a Bluetooth device.

What Is Pairing?

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Pairing with a device is the process in which you securely confirm the identity of a device with which you want to allow data access or control.

Some devices use access codes to prevent unwanted connections, validating the identity of a connecting device. However, product designers sometimes skip this access-code step to improve the device's user experience.

After you pair devices, they may be in a connected or disconnected state. Pairing only indicates that two devices have established the identity of each other; it does not reflect whether two devices are currently connected.

You can think of pairing as selecting which devices you trust, allowing them to control and access data from your device.

What Are Bluetooth Profiles?

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Bluetooth profiles are sets of add-on Bluetooth capabilities or functions which devices can choose to support.

Popular Bluetooth profiles include:

Comparison of Bluetooth Profiles
ProfileUse Case
Advanced Audio Distribution Profile (A2DP) High-Quality Stereo Sound for headsets, hearing aids, car audio, voice recording
Headset Profile (HSP) Low-Quality Mono Sound for headsets
Hands-free Profile (HFP) Low-Quality Mono Sound for hands-free operation of mobile phones
Human Interface Device Profile (HID) Mice, keyboards, joysticks, game controllers, and remotes
Audio/Video Remote Control Profile (AVRCP) Remotely control audio/video, such as for a car audio system
File Transfer Profile (FTP) Share and manage files

What Are Bluetooth Codecs?

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A Bluetooth audio codec is a hardware or software algorithm used for compressing and decompressing an audio stream to find a compromise between audio quality, bandwidth usage, and latency.

High bandwidth usage (bitrate) combined with a lousy signal can result in skipping or distorted audio.

On the other hand, a high latency (slow) codec would delay audio for video game voice-chat or movies.

Popular Bluetooth audio codecs include:

Comparison of Bluetooth Codecs
CodecMax BitrateBit DepthMax FrequencyDeveloped By
SBC (A2DP Default) 345 kbps 16-bit 48 kHz Bluetooth Special Interest Group
LC3 (Bluetooth Low Energy's SBC successor) N/A Up to 32-bit 48 kHz Bluetooth Special Interest Group
aptX 384 kbps 16-bit 48 kHz Qualcomm
aptX LL (low latency) 352 kbps 24-bit 48 kHz Qualcomm
aptX HD 576 kbps 24-bit 48 kHz Qualcomm
aptX Adaptive 420 kbps 24-bit 48 kHz Qualcomm
FastStream (SBC with mic support) 212 kbps 48-bit 48 kHz Qualcomm
AAC 320 kbps 24-bit 44.1 kHz Various
LDAC 990 kbps 24-bit 96 kHz Sony
Scalable Codec 512 kbps 24-bit 96 kHz Samsung

What Is Bluetooth Low Energy?

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Bluetooth Low Energy (Bluetooth LE or BLE) is distinct from classic Bluetooth. It is optimized for low-energy applications such as sensors and beacons for maximum battery life and power consumption.

In early 2020, the Bluetooth Special Interest Group announced that Bluetooth LE would support broadcasting audio to multiple devices and support hearing aids.

How Does Bluetooth Differ From Wi-Fi?

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Bluetooth is more energy-efficient than Wi-Fi but has much lower bitrates. Additionally, Wi-Fi supports different communication protocols, which are designed for Internet and local area network access.

What Causes Bluetooth Interference?

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Common Causes and Fixes for Bluetooth Interference
Cause of Bluetooth interferenceHow to fix it
High Wi-Fi transmission power Reduce the transmission power of your wireless router.
Near Wi-Fi router Signal strength increases as you approach the competing wireless transmitters; move further from wireless routers.
Near multiple Wi-Fi routers Multiple routers may be taking up too much of the wireless spectrum; move further from wireless routers.
Too far from the source The signal will weaken as you get further from the connected device; move the devices closer together.
Obstacles in path Signals will become weaker or blocked if they have to go through obstacles such as walls; move the devices to a location in which they have a line of sight between each other.
Other wireless devices nearby Move away from other wireless devices which will compete over the same spectrum.
Microwave oven running nearby Get a new microwave with better shielding or move further from the microwave.

Can You Amplify a Bluetooth Signal?

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You can extend the range of a Bluetooth signal by using a Bluetooth Transmitter Receiver. These are typically designed to support specific audio profiles and codecs, which will only help particular use cases.

Is Bluetooth Secure?

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Modern Bluetooth versions (version 2.1 and newer) use public-key cryptography to encrypt communications. Security vulnerabilities continue to be discovered over time.

Like most technologies, using up-to-date hardware and software on your devices will reduce any chance of eavesdropping and other attacks. You'll need to evaluate your acceptable level of risk when deciding how to use wireless technologies.

The National Institute of Standards and Technology released a Guide to Bluetooth Security to help the more at-risk organizations create a good security process and understanding.