Bluetooth

Bluetooth is a wireless communication system used for small or handheld devices. It allows nearby devices to communicate quickly and efficiently on a private network. Bluetooth is commonly used with phones, headsets, keyboards, and speakers. It works best when devices remain in close proximity and is convenient for situations in which wired connections would be troublesome.

History of Bluetooth

Bluetooth’s origins can be traced to the frequency-hopping spread spectrum (FHSS) technique patented in 1942. FHSS was originally designed as a mechanism for controlling a torpedo through radio signals in a way that the frequency could not be jammed. The idea of a radio signal that consistently jumps between frequencies is essential to Bluetooth communications.

In the early 1990s, several telecommunications companies, including Nokia, Ericsson, Intel, Toshiba, and IBM, wanted to develop a form of wireless communication between cellular phones and computer devices. However, they understood that for this form of communication to be commercially successful, it would have to work with devices running on all network providers. For this reason, the companies decided to form a special interest group (SIG) to further this development. The SIG was finalized in 1998, and the first Bluetooth technology was developed in 1999.

The name “Bluetooth” was inspired by an ancient Danish king, Harald Blåtand, who united the surrounding Danish tribes for a common goal. The SIG thought the name was appropriate for a technology uniting all the major technology firms of the time. Bluetooth was meant to be a temporary moniker and was supposed to be replaced as soon as the marketing team found a better label for the new technology. However, the name stuck, and soon it was easier to continue referring to the devices as Bluetooth transmitters. The Bluetooth symbol found on most Bluetooth-enabled devices was created from the runic initials of King Blåtand.

The SIG continued to invest, develop, and attract new members. It was shipping millions of functioning units per week by 2005. Two years later, with the integration of Nokia’s Wibree technology into Bluetooth, the SIG gained access to new technology that drastically reduced the amount of power necessary for a Bluetooth device to function. This allowed Bluetooth devices to run on minuscule, common coin-cell batteries.

Low-power Bluetooth devices were further improved with the release of Bluetooth 5.4 in 2023. That year, more than five billion Bluetooth devices were shipped annually, according to Statista. These devices are used in large numbers of cell phones, headphones, microphones, speakers, clocks, keyboards, computer mice, tablets, printers, and computers.

How Bluetooth Works

Bluetooth devices operate in the same transmission frequency range as Wi-Fi Internet and microwaves, constantly jumping between frequencies to avoid interference from other devices. A Bluetooth device contains both a receiver and transmitter, which operate as long as the device is turned on. These devices form a central–peripheral (formerly referred to as master-slave) style network. These networks contain one controlling device, called the master device, and up to seven actively controlled devices, called slave devices. Networks containing one master device with the potential for up to seven slave devices are called piconets. Bluetooth-enabled devices may belong to multiple piconets at a time, as either a master device or a slave device. Piconets may also contain many more slave devices, on the condition that only seven or fewer slave devices are operating on the network. An example piconet could include one smartphone as the master device, with a Bluetooth headset and a car stereo as slave devices.

In order to form a piconet, slave devices need to synchronize with a master device. While this process may be accomplished via a wire in traditional networking, Bluetooth devices use a system of inquiry and inquiry scan. Potential slave devices constantly emit an inquiry signal. This is a signal that identifies the device, its basic purpose, but it does not indicate whether the device is already paired. Master devices then perform inquiry scans, which involve scanning all known frequencies used by Bluetooth devices for inquiries. The two devices then exchange information, and the master device displays this information to its user, with the option to allow the devices to further interact. If the user allows the interaction, the devices are paired.

For example, a smartphone user wants to pair a smartphone with a wireless Bluetooth headset. The headset, a slave device, is broadcasting its inquiry at all times. The user tells the smartphone to scan for new devices, and the smartphone’s inquiry scan finds several nearby devices. One of these is identified as a Bluetooth headset. The user then pairs the smartphone with the headset, allowing the two to function together. Updates to Bluetooth (version 6.0 and later, released from 2024 onward) have introduced high-precision distance measurement using channel sounding, allowing devices to determine location with centimeter-level accuracy.

Alternatives to Bluetooth

While Bluetooth once dominated the market for short-range wireless electronic communication, several competing technologies have developed. The most prominent of these are near field communication (NFC) and Wi-Fi Direct. NFC allows two devices to communicate at a short range, but at relatively low data transfer rates. However, it requires the two devices to be within inches of each other. For this reason, NFC is often used as a method of secure, wireless payment. Credit card or bank account information stored on a smartphone or other mobile device simply needs to be held up to a corresponding terminal for payment to be processed. This limited short-range communication, however, means that NFC is not a direct replacement for   Bluetooth in most use cases.

Wi-Fi Direct is more similar to Bluetooth than NFC and is considered more of a threat to Bluetooth’s market share. Devices enabled with Wi-Fi Direct can wirelessly communicate with each other in areas that lack a traditional Wi-Fi network. They can also communicate with most Wi-Fi-enabled devices, just as if a traditional Wi-Fi network were in place. Most importantly, Wi-Fi Direct generally allows higher data transfer speeds than many Bluetooth versions, though the difference depends on the specific Bluetooth version used.

Bibliography

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“How Does Bluetooth Work?” Scientific American, 5 Nov. 2007, www.scientificamerican.com/article/experts-how-does-bluetooth-work/. Accessed 13 Apr. 2026.

Negrin, Avi. “Just released: Bluetooth® Core 6.2.” Bluetooth, 4 Nov. 2025, www.bluetooth.com/blog/just-released-bluetooth-core-6-2/. Accessed 13 Apr. 2026.

“Think Robotics.” “Latest Version of Bluetooth: Bluetooth 6.0 Features & What’s New in 2025.” ThinkRobotics.com, 12 Dec. 2025, thinkrobotics.com/blogs/indepths/latest-version-of-bluetooth-bluetooth-6-0-features-whats-new-in-2025. Accessed 13 Apr. 2026.