A: Pair the first device with ZEB-BH500 headset.
Once the connection is complete, turn OFF the BT in the first device.
Now turn ON the BT of the second device and pair it with the headset.
Once paired, simply turn ON the BT of the first device and it will automatically connect to the headset.
Thus two devices would be now connected to the headset.
A: +5V DC.