debian: pair bluetooth audio device

a_bluetooth.sh

su
apt install bluetooth pulseaudio-module-bluetooth
/etc/init.d/bluetooth stop
pactl unload-module  module-bluetooth-discover
pactl load-module  module-bluetooth-discover
/etc/init.d/bluetooth start
exit

bluetoothctl
[bluetooth]# untrust F8:DF:15:C7:1C:3D
[bluetooth]# remove F8:DF:15:C7:1C:3D
[bluetooth]# pair F8:DF:15:C7:1C:3D
[bluetooth]# trust F8:DF:15:C7:1C:3D
[bluetooth]# connect F8:DF:15:C7:1C:3D

bluetooth.conf

<!-- /etc/dbus-1/system.d/bluetooth.conf -->
<!-- This configuration file specifies the required security policies
     for Bluetooth core daemon to work. -->
<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>

  <!-- ../system.conf have denied everything, so we just punch some holes -->

  <policy user="root">
    <allow own="org.bluez"/>
    <allow send_destination="org.bluez"/>
    <allow send_interface="org.bluez.Agent1"/>
    <allow send_interface="org.bluez.MediaEndpoint1"/>
    <allow send_interface="org.bluez.MediaPlayer1"/>
    <allow send_interface="org.bluez.Profile1"/>
    <allow send_interface="org.bluez.GattCharacteristic1"/>
    <allow send_interface="org.bluez.GattDescriptor1"/>
    <allow send_interface="org.bluez.LEAdvertisement1"/>
    <allow send_interface="org.freedesktop.DBus.ObjectManager"/>
    <allow send_interface="org.freedesktop.DBus.Properties"/>
  </policy>

  <!-- allow users of bluetooth group to communicate -->
  <policy group="bluetooth">
    <allow send_destination="org.bluez"/>
  </policy>

  <policy at_console="true">
    <allow send_destination="org.bluez"/>
  </policy>

  <!-- allow users of lp group (printing subsystem) to 
       communicate with bluetoothd -->
  <policy group="lp">
    <allow send_destination="org.bluez"/>
  </policy>

  <policy context="default">
    <allow send_destination="org.bluez"/>
  </policy>

</busconfig>

https://computingforgeeks.com/connect-to-bluetooth-device-from-linux-terminal/

https://askubuntu.com/a/1128018/359571

https://raspberrypi.stackexchange.com/a/67665/13094

untrust F8:DF:15:C7:1C:3D
remove F8:DF:15:C7:1C:3D
pair F8:DF:15:C7:1C:3D
trust F8:DF:15:C7:1C:3D
connect F8:DF:15:C7:1C:3D

untrust F4:BC:DA:1A:B9:2D
remove F4:BC:DA:1A:B9:2D
pair F4:BC:DA:1A:B9:2D
trust F4:BC:DA:1A:B9:2D
connect F4:BC:DA:1A:B9:2D