Qualified Dual-mode Bluetooth Stack

On Linux, working with Bluetooth devices typically involves the BlueZ. The operating system detects and initializes the controller, while BlueZ acts as the central service that exposes Bluetooth functionality to applications. Although the kernel provides a uniform HCI interface for controllers connected via USB, UART, or SDIO, applications communicate with BlueZ over D-Bus and other high-level APIs to perform tasks such as device discovery, pairing, and accessing GATT services. BTstack, our proprietary user-space Bluetooth Host Stack, follows a different approach: it interacts directly with Bluetooth controllers at the HCI level. For embedded Linux systems, it provides custom HCI transport implementations for UART and USB to communicate with the controller. The direct access enables BTstack to handle controller initialization, including firmware download and vendor-specific setup steps for a wide range of devices, which are often required on embedded platforms. This gives developers full control over the complete Bluetooth stack within their application.

We visited the Embedded World Exhibition in Nuremberg again this year as an independent Bluetooth Host Stack vendor. Events like this are a great opportunity to step outside of project threads and long technical email exchanges and actually meet the people behind them. It adds a much-needed personal dimension to the work we usually do remotely. It’s also a place where you quickly find others on the same wavelength — engineers dealing with the same practical realities of hardware and Bluetooth chip restrictions. As always, we had many discussions about solutions and possibilities. And yes, we’ll keep advocating for a few things we believe would make many developers’ lives easier — such as a very simple GPIO-toggle-based time synchronization mechanism for LE Audio TWS, as well as better support for forwarding Bluetooth Classic audio to LE Audio.

The Web has evolved into a powerful platform for hardware interaction, yet Classic Bluetooth and LE Audio support have long remained one of the last frontiers trapped in native code. Breaking that barrier would open the door to a new class of connected Web experiences – connecting your Bluetooth headphones, sensors, and controllers directly through the browser, with no drivers, or system dependencies could enable innovation that isn’t gated by operating systems but fueled by open standards and creativity.