An interesting invention
While having dinner with friends, I saw a diabetic friend using a blood glucose meter to check their blood sugar, and we started talking about Bluetooth. I occasionally use this technology, but who actually invented it? Why is it called “Bluetooth”? There is actually a fascinating story behind it.
The original idea for Bluetooth was to solve the messy problem of connecting various devices with cables. Back in the 1990s, as mobile phones, computers, and headphones became more prevalent, transferring a contact list or connecting a headset required different cables, which was particularly troublesome. The company Ericsson noticed this issue.
In 1994, Ericsson began to explore a cheap and energy-efficient wireless connection method. The engineer who truly developed the technology was Jaap Haartsen, known as the “Father of Bluetooth”.
So how did the name “Bluetooth” come about? Interestingly, it does not stem from technology but from a Danish king from a thousand years ago—Harald I, nicknamed “Bluetooth King”. He unified the tribes of Denmark and Norway and converted them to Christianity. This king earned the nickname “Bluetooth” because of a dark-colored tooth.
Interestingly, in 1997, an Intel engineer named Jim Kardach was promoting this new technology and happened to read a novel about Viking history called “The Long Ships”, which mentioned this Bluetooth King. He thought that this technology, like King Bluetooth unifying tribes, could connect devices like mobile phones, computers, and headphones together. This metaphor was well-received, and thus the temporary name “Bluetooth” stuck.
Even the Bluetooth logo is related to this king—it is formed by combining the initials H and B of his name using ancient Nordic symbols: ᚼ and ᛒ.
Although Ericsson invented Bluetooth, they knew they couldn’t promote it alone. So in 1998, they teamed up with Intel, IBM, Nokia, and Toshiba to establish the “Bluetooth Special Interest Group (SIG)” to set standards and promote the technology.
The first Bluetooth product was the Bluetooth headset launched by Ericsson in 1999, which gradually became popular in mobile phones, computers, keyboards, speakers… now it is almost ubiquitous.
In summary, Bluetooth is a cool story named after a thousand-year-old king’s nickname, which was realized through collaboration with major companies to achieve “wireless unification”. You might be curious: can Bluetooth connect multiple devices at the same time? The answer is: yes! But there are indeed limitations depending on the situation.
First, we need to clarify two concepts:
· Pairing: Like adding friends, a mobile phone can pair with dozens of devices and remember them. · Connection: This is the actual establishment of communication, and how many devices can be connected depends on the capabilities of the main device. Generally speaking, classic Bluetooth can connect about 7 devices simultaneously, but that is a theoretical value. If several devices are transferring large files, it may lag. Bluetooth Low Energy (BLE) is designed to connect more devices, suitable for small devices in smart homes that occasionally send data.
In our daily use, a mobile phone can connect to headphones, a watch, a keyboard, and a mouse simultaneously, typically handling 3-5 devices without issue. However, audio transmission is an exception: traditional Bluetooth generally can only transmit one audio stream to one headset or speaker at a time, not to two simultaneously. However, the new generation of “LE Audio” technology can now broadcast audio from one phone to multiple headsets!
So to summarize: Bluetooth can connect multiple devices simultaneously (headphones + watch + keyboard… no problem), theoretically up to 7 devices, but practically 3-5 is more stable. For music, traditional Bluetooth can only do one-to-one, but new technology can now do one-to-many. Next time you want to connect a keyboard, mouse, and headphones at the same time, feel free to do so—just check if your devices support LE Audio if you want two people to use two Bluetooth headsets to listen to the same music from one phone.
Written in Tianjin, 2025-10-03 noon