Using the BTD-400 and BTD-400 on Ubuntu Linux and other distributions
  
  Ubuntu
  Our BTD-400 and BTD-400 USB Bluetooth adapters are compatible with Ubuntu Linux
  and derivatives.  The required drivers are included with Ubuntu 12.04 and
  later.
  
  For other Linux distributions, you’ll need to install the BlueZ Bluetooth stack
  and the BlueMan Bluetooth Manager.  Consult your distribution’s web site
  to see if the Bluez and Blueman software are available as a ready-to-install
  software package.
  
  Turning on Bluetooth
  1. Plug in the Bluetooth adapter
  2. Click the Bluetooth Icon in the toolbar
  3. Click "Turn on Bluetooth"
  
  Connecting a Device
  1. Click the Bluetooth icon in the menu bar and select
  Set Up New Device.
  2. Make the other Bluetooth device discoverable or visible and place it within
  10 meters (about 33 feet) of your computer. Click Continue. Your computer will
  begin searching for devices.
  3. If there are too many devices listed, use the Device type drop-down
  to display only a single type of device in the list.
  4. Click PIN options to set how a PIN will be delivered to the
  other device.
  5. The automatic PIN setting will use a six-digit numerical code. A device with
  no input keys or screen, such as a mouse or headset, may require a specific PIN
  such as 0000, or no PIN at all. Check your device's manual for the proper setting.
  6. Choose an appropriate PIN setting for your device, then click
  Close.
  7. Click Continue to proceed. If you did not choose a preset
  PIN, the PIN will be displayed on the screen.
  8. If required, confirm the PIN on your other device. The device should show
  you the PIN you see on your computer screen, or may prompt you to enter the PIN.
  Confirm the PIN on the device, then click Matches.
  
  You need to finish your entry within about 20 seconds on most devices, or the
  connection will not be completed. If that happens, return to the device list
  and start again.
  
  9. A message appears when the connection successfully completes. Click
  Close.
  
  Set Playback Devices
  
  1. Click the Speaker icon on the toolbar and select Audio Setup
  2. Select the Audio Hardware Setup Tab
  3. Click Profile drop-down box and select Off
  
  Linux Driver Installation
  The Linux kernels after June 2012 have the drivers for the Broadcom Bluetooth
  chipset.  They are present in Linux kernel versions 3.0.x, 3.2.x and 3.4.x. 
  It also present in Linux kernels 4.0 and above so no driver installation is required.
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  KDE and GNOME
  The KDE and GNOME desktop environments provide Bluetooth configuration and management
  utilities.  If not installed by default, you will need to install them with
  your Linux distribution’s package manager.
  Debian, Linux, Ubuntu and Ubuntu derivatives usually have the Bluez Bluetooth
  stack installed by default along with a Bluetooth manager.  We recommend
  opening a terminal window and typing the following commands to install the necessary
  packages:
   
  
  
  The above command will install the Bluez Bluetooth stack and the Blueman Bluetooth manager.  If they are already installed, apt-get will report that the packages are already present on your system.
Fedora
Fedora, Red Hat Enterprise and CentOS have their own packages available.  The Fedora Project Wiki has an article on using Bluetooth and the required packages, below:
Bluetooth on Fedora
Red Hat Enterprise and CentOS 
Red Hat Enterprise and CentOS have the Bluez Bluetooth stack that can be installed via the package management tool.