Bluetooth is a technology that most of us are familiar with. It’s useful for file transfers between smartphones and tablets, perfect for connecting portable speakers and headphones, and great for hooking up a wireless mouse or keyboard to your PC or laptop. But what is Bluetooth?
In a nutshell, it’s a short-range wireless communication technology that uses radio waves to transmit information, much like Wi-Fi. But where that wireless standard operates semi-permanent networks and can do so over a vast distance, Bluetooth is typically more limited and personal than that.
It arguably has a much cooler name too. The word Bluetooth comes from the epithet of tenth-century Danish king, Harald “Bluetooth” Gormsson, who united the Danish tribes into a single Kingdom. Just as he did so, Bluetooth technology was designed to unite otherwise disparate wireless devices. The logo is even modeled after the Nordic runes for his initials.
How does Bluetooth work?
Bluetooth works by sending information over ultra-high-frequency radio waves and operates within the industrial, scientific and medical (ISM) radio bands. It works between the 2.4 and 2.485 GHz frequencies, much like many Wi-Fi devices do, which can create problems with interference when both technologies are running simultaneously or if multiple devices are operating within the same area.
Where Wi-Fi operates asymmetrically (with a singular access point and multiple devices) Bluetooth typically works symmetrically, with one Bluetooth device connecting to another. Although up to eight devices can be connected on a single personal area network (PAN), in the case of smartphones, it typically means connecting two handsets together for file transfers, or one smartphone and a Bluetooth speaker.
Unlike Wi-Fi, Bluetooth connections do not use up your cellular data package because they aren’t transmitting data over the airwaves in the same way. Bluetooth is exclusively device to device transmission with no intermediaries.
Bluetooth typically operates over short distances to conserve power. Although it is possible for Bluetooth to operate within a 100 meter range, that is very uncommon, with most devices typically operating within 10 meters of one another.
To make snooping on its radio transmissions more difficult, Bluetooth utilizes adaptive frequency-hopping spread spectrum which automatically changes the radio frequency as many as 1,600 times per second. Data transmitted is split into packets and then transmitted across the randomly selected channels, avoiding any that are particularly busy. This is just one area that has been improved through successive generations of Bluetooth technology.
What uses Bluetooth?
Although originally designed with a specific use in mind, Bluetooth today is used in all manner of devices, both smart and not, for sending data across short distances. Your wireless speaker and wireless headphones communicate with your smartphone or home hub using Bluetooth technology and if your car is only a few years old, it likely offers Bluetooth connectivity to its sound system — although adding it to older cars is easy too.
Most laptops come equipped with Bluetooth built in to make it easier to connect wireless peripherals like keyboards, mice, and in some cases printers and scanners. Desktop PCs sometimes have it too, but more commonly you’ll see Bluetooth added to them via a USB dongle.
Most game consoles do use Bluetooth in some manner for wireless connections, but only the PS4 supports third-party Bluetooth devices natively. Here’s how to connect yours to your PS4.
More recently, internet of things (IoT) devices have begun to support Bluetooth technology. It can be a low-power way of keeping them connected to a central hub or mobile device. However, they are just as likely to be connected to your Wi-Fi network, especially if powered through a mains socket.
Bluetooth was first conceived in its conceptual form in the late 1980s as a way to create wireless headphones, but it wasn’t until 1994 that it was realized as an actualized technology by a team at Ericsson headed by Dr. Jaap Haartsen. It would take a further four years for the specifications for Bluetooth compatible devices to be finalized by the Bluetooth Special Interest Group. At that time it was made up of five companies: Ericsson, IBM, Intel, Nokia and Toshiba. Today more than 30,000 companies are members.
Bluetooth 1.0 was iterated upon as 1.0a and 1.0b in 1999 to correct some minor problems, and again as version 1.0b + CE in 2000. The first Bluetooth-equipped mobile phones, PC cards, and laptops were released that same year. More products would follow in the ensuing years, including the long-desired Bluetooth headset which helped kick-start the development of the standard in the first place.
The Bluetooth 2.0 standard was revealed in 2004 and introduced Enhanced Data Rate, which improved transfer speeds to up to 3Mbit per second. It also lowered power requirements, which would be a continual aim of Bluetooth developers in the years to come.
Speeds were again improved by Bluetooth 3.0 in 2009, increasing theoretical data rates to 24Mbit per second, though it and its successor, Bluetooth 4.0, both leveraged the 802.11 standard (more commonly used in Wi-Fi) for the fastest transfers.
Arguably the biggest upgrade with the fourth-generation of Bluetooth though, came with the 4.2 iteration: Bluetooth Low Energy. Today most smartphones around the world support the standard and it allows for similar coverage and similar bandwidth while making big reductions in power requirements for data transmission — by between 50 and 10,000 percent depending on use case. This was designed to not only reduce Bluetooth demands on user-controlled devices, but to make it easier for portable speakers, fitness trackers, and internet of things devices to operate for far longer between charges.
Bluetooth 5 was introduced in 2016 with improved security and greater flexibility for speed and range. Supporting devices can sacrifice one for the other, increasing either by two to four times if needed. Bluetooth 5.1 was introduced in late January 2019 and added a feature to help find the physical location of transmitting devices, which could be useful for finding lost items fitted with a Bluetooth tag. It could also be leveraged to trigger the display of relevant content on information displays in public spaces like museums.
One of the core tenets of Bluetooth technology is that they are all backwards compatible. Any modern Bluetooth device, no matter which version it supports, will also support devices using the previous versions of the technology.