How to solve the audio problem in Zoom Cloud Meeting for Android TV

OK. I solved this problem by try and error myself.

In summary, you need a microphone present to enable Zoom audio communication.

I have tested 2 TV Boxes, one with Android 10, another with Android 8.0.1. The microphone I used is Logitech H310 headset with microphone.

The details are as following:

1. [Edited on 8/27/2020] There are 2 USB 2.0 ports on TV Box. One is Master, where you can plug USB headset and microphone into. The other is slave which is used for PC debugging and local upgrade. You cannot use the slave USB port for microphone. Unfortunately, there is no mark on the box, so you have to try it yourself.


2. Test the microphone is working on TV Box. I use Skype to test.


3. Open Zoom.


4. (For Android 8.0.1 only, it is strange) Click join meeting, scroll down to find "Do not connect to audio). It is unselected by default, click it to make it selected.


5. Join a meeting.


6. Click the participant, you should see yourself with a microphone icon. If you cannot see the microphone icon, you can unplug the usb microphone and plug it again.


7. Once you can see the microphone icon for yourself, click the "join audio" and click "call over Internet". Then you will see the "join audio" disappear and a microphone icon on the bottom left with "mute".


8. Now you will be able to hear the sound on your headset. And you can speak over the microphone.


9. (For Android 10, it is also strange) If you unplug and plug microphone after you already connected to Zoom by microphone. You can see a prompt saying "USB audio AV is plugged in..." and ask "Yes" or "No". If you click No this time, it will say "connect by default channel". Then you can hear the voice communication through both the TV speaker and the headset.


10. (For Android 8.0.1) I can hear the voice communication on headset, but I still cannot make the speaker to work.

I will mark this one as answer to myself.