Bluetooth: How it works and why we still need it.

German Autolabs
6 min readJun 24, 2020


It’s 2020 — Why are we still relying on this strange, archaic platform?

xkcd: Bluetooth

It started 1000 years ago.

Fact: Bluetooth first appeared in Denmark around 950 AD, helping to spread Christianity to Jutland and Zealand, and cementing the rule of a new dynasty across Denmark and Norway. King Harald Bluetooth was the son of Gorm, and ruled in a state of blissful ignorance that his name would be pinched by a team of Ericsson engineers 1000 years later.

The runic-inspired Bluetooth logo

Even Harry’s initials in rune form give us the logo for our own contemporary version of Bluetooth. It’s hard not to feel a little sorry for him. How would you like your name attached to a widely-derided, misunderstood bit of future tech?

Here are some actual quotes from our developers on the subject of Bluetooth:

- Bluetooth? It feels like a needy partner. It’s just so much effort compared to what you get back.

- Bluetooth is just a really unsexy technology. Nobody wants to know about it, everybody just wants it to work.

- Come to lunch with the developers, you’ll get hours and hours of Bluetooth related “content”.

And it’s not just misanthropic, sallow-faced developers with an axe to grind against Bluetooth. Judging by the number of venting posts on the net, consumers don’t exactly love it either. But before we all pile in with the hate, it’s worth taking a moment to consider where the technology came from.

Bluetooth in cable form.

Father was a cable.

More mature readers will recall good old serial port cables. Very similar to the more widely recognised VGA cable, serial port cables were for connecting printers, mice and so on, and were also known as RS-232 cables. Bluetooth was basically a wireless version of RS-232. Even today, the kinds of connections possible with Bluetooth remain very similar to the old serial port standard. Sometimes, we haven’t come as far as it seems.

So how did we get to the point where Bluetooth has become the connection at the heart of the entire Internet-of-Things ecosystem? One word, beginning with A: Audio. Transferring audio wirelessly and instantly was just not possible without a cable. Enter Bluetooth. Once it became apparent that the great audio transfer riddle could be solved, another little company, also beginning with A, got behind the technology: Apple.

An early Apple supercomputer

As soon as Bluetooth Low Energy had proven itself on the battlefields, Apple stuffed it into their new phone — a little known device called the iPhone. No sooner than you could say total global domination, and Bluetooth had become kind of a big deal. As an aside, Apple have previous with this kind of thing. Back in ’98 when they were knocking out their first brightly-coloured iMacs, Apple needed a new way to connect things to their boxes to replace the very unsexy SCSI ports they had been using. Someone went shopping at Intel, found a struggling little standard called Universal Serial Bus, and thus USB became the one port to rule them all.


Bluetooth, black heart.

Device connection is a major problem for everyone: developers, manufacturers, users. Cables are not a good thing, especially in cars. Gravity has a way of playing hell with them, which leaves wireless connection options. That means our old friend, Bluetooth.

The majority of our software efforts with Bluetooth at German Autolabs concerns connection management for users. People these days have a large number of devices connected to their smartphones via Bluetooth. The irony is: the Bluetooth platform itself is just not very accommodating when it comes to connections.

Here’s the rub: mobile vendors want to make life easier for software developers by limiting their options. In an attempt to make things work efficiently, vendors provide just a small selection of presets to choose between.

That’s great for simple applications — they do indeed get to work in a more standardised manner. Having limited presets stops every developer coming up with their own unique way of configuring the Bluetooth connection.

Unfortunately, this method takes away a lot of options for developers who want to do something non-standard with Bluetooth. Our product, Chris, relies heavily on a non-standard, innovative use of Bluetooth.

Early-stage drawing board for Chris; soldering irons and Bluetooth chipsets in the foreground

Why we have to hack Bluetooth

Take two key bits of mobile technology: voice and music. On the face of it they both seem pretty similar, but the way they’re implemented in mobile technology is completely different.

When you have a voice conversation on your phone, the audio takes a totally separate route through both the Bluetooth stack and the phone operating system than your music does.

Chris in action, courtesy of hacked up Bluetooth

For many developers, this isn’t a problem. They either do music, or they do voice. Our device Chris requires both, and we need to be able to switch very quickly between the two.

Here’s a real world example. Suppose you’re driving along, enjoying the scenery, listening to music being played through Chris. Then you get an urge to send Dad a hello, so you say:

“Hey Chris, send a WhatsApp message to Dad.”

As soon as you say Hey Chris, the device needs to switch from music to voice mode immediately. It’s our job to make this switch happen ASAP — but sometimes the mobile operating system doesn’t comply as fast as we need it to.

We pull some tricks with the Chris hardware so that we can store the WhatsApp message to Dad part and then play it internally when the connection is ready. This way we can bypass the lag in the Bluetooth and compensate for the shortcomings of the operating system.

Creating all these hacks through the Bluetooth stack requires an enormous amount of dedication from our R&D and development teams, and sometimes it feels like a thankless task. There is hope though…

Laptop, smartphone, 1000-year-old runic symbol

The future is bright, the future is blue.

There is light at the end of the tunnel. Bluetooth is constantly being worked on and iterated. The slightly dubiously named Bluetooth Special Interest Group is in charge of developing the technology. The latest version is Bluetooth 5.0 and compared to its predecessor, the rather slothful sounding Bluetooth 4.2 Low Energy, it’s twice as fast, has four times the range and can transfer eight times as much data.

Range has been boosted to around 240m, meaning your gadgets should work much further away. Well that’s the theory anyway. It also allows for whole-home coverage for IoT devices such as home lighting, smart fridges, central heating and the like. A rather nice bonus of Bluetooth 5.0 is that it grants the ability to connect more than one pair of wireless headphones to a single sound source. No more solo podcast listening on the plane.

For all of these supposed advances in Bluetooth, one thing is clear: the technology still has a long way to go. And until this happens, one thing is for certain: we’ll keep pushing the boundaries of the technology. And coming up with the odd hack, here and there.

German Autolabs builds voice assistance solutions for professional drivers. For more information, visit Thanks for reading.



German Autolabs

We build logistics voice assistance for mobile workers.