Which communication protocol did we use to send data over a Bluetooth connection? What kind of address do Bluetooth devices have? What was the use of List Picker inside the Voice Control Bot...

Which communication protocol did we use to send data over a Bluetooth connection? What kind of address do Bluetooth devices have? What was the use of List Picker inside the Voice Control Bot application? On the client side, which function is used to connect the client socket to the server socket? What is the default Bluetooth name of your RPi?