Bluetooth
On models that support it, GOLDENRADIO can send the audio it is receiving to a Bluetooth device (headphones or a speaker), or, on the contrary, receive audio from a Bluetooth device (for example a smartphone) and play it from its speaker, as any Bluetooth speaker would do. Bluetooth is turned on and off by the switch on the Settings page; if your model does not have Bluetooth hardware, the switch remains disabled.

Below is a description of the various components involved.
BT button
With Bluetooth turned on, on ULTRA models a BT button appears on the main page: on the HF, AIR and VHF bands it is in the line under the frequency, in place of the second switch (see the chapter Main page); in FM it is instead in the volume and battery row. The writing on the button changes depending on the mode: BT-TX when the radio transmits its own audio, BT-RX when it receives it.
BT-TX
This is the default mode as soon as you turn on Bluetooth. The radio transmits the audio of what you are listening to at that moment to a paired Bluetooth device (headphones, a speaker), whatever band or mode it is — it's not just tied to FM.
BT-RX
In this way the radio does the reverse path: it receives audio from an external Bluetooth device and plays it from its own speaker, like a Bluetooth speaker. While in BT-RX, radio reception audio remains muted.
"BT-RX" window
Switching from BT-TX to BT-RX a full-screen window appears with the words "BT-RX", "Bluetooth receiver active" and "Radio audio muted", and a red STOP button.
Switch from BT-TX to BT-RX
Tap the BT button while it shows BT-TX: the radio will beep and the "BT-RX" window described above appears.
Return to BT-TX
Tap STOP in the "BT-RX" window, or — if you've somehow returned to the main page with the window still open — tap the BT button again, now labeled BT-RX: in either case the radio beeps and returns to BT-TX, with the reception audio resuming.