HARDWARE
========

The Bumble Host connects to a controller over an [HCI Transport](../transports/index.md).
To use a hardware controller attached to the host on which the host application is running, the transport is typically either [HCI over UART](../transports/serial.md) or [HCI over USB](../transports/usb.md).
On Linux, the [VHCI Transport](../transports/vhci.md) can be used to communicate with any controller hardware managed by the operating system. Alternatively, a remote controller (a phyiscal controller attached to a remote host) can be used by connecting one of the networked transports (such as the [TCP Client transport](../transports/tcp_client.md), the [TCP Server transport](../transports/tcp_server.md) or the [UDP Transport](../transports/udp.md)) to an [HCI Bridge](../apps_and_tools/hci_bridge.md) bridging the network transport to a physical controller on a remote host.

In theory, any controller that is compliant with the HCI over UART or HCI over USB protocols can be used.

HCI over USB is very common, implemented by a number of commercial Bluetooth dongles.

It is also possible to use an embedded development board, running a specialized application, such as the [`HCI UART`](https://docs.zephyrproject.org/latest/samples/bluetooth/hci_uart/README.html) and [`HCI USB`](https://docs.zephyrproject.org/latest/samples/bluetooth/hci_usb/README.html) demo applications from the [Zephyr project](https://www.zephyrproject.org/), or the [`blehci`](https://mynewt.apache.org/latest/tutorials/ble/blehci_project.html) application from [mynewt/nimble](https://mynewt.apache.org/)

Some specific USB dongles and embedded boards that are known to work include:

* [Nordic nRF52840 DK board](https://www.nordicsemi.com/Products/Development-hardware/nrf52840-dk) with the Zephyr `HCI UART` application
* [Nordic nRF52840 DK board](https://www.nordicsemi.com/Products/Development-hardware/nrf52840-dk) with the mynewt `blehci` application
* [Nordic nrf52840 dongle](https://www.nordicsemi.com/Products/Development-hardware/nRF52840-Dongle) with the Zephyr `HCI USB` application
* [BT820 USB Dongle](https://www.lairdconnect.com/wireless-modules/bluetooth-modules/bluetooth-42-and-40-modules/bt800-series-bluetooth-module)

However, many Bluetooth controllers do not fully implement the complete set of Bluetooth specifications. To help us improve compatibility and expand support, we are collecting data on user hardware.

We would greatly appreciate it if you could share the capabilities and purchase details for any controllers you have available for testing. We will later build a capability table here.
