Hello,
1- About the buzzer control, this function is not open now.
2- About the P1 connector, it doesn’t need to be changed normally. Please switch it to PWR and it should work.
3- About the error response. Please try this serial port debugging software, download link is as follows: https://www.stoneitech.com/media/upload/Download/Software%20%26%20Driver/UART%20Communication%20Software%20-% 20SSCOM32.rar
I tried this software and it worked fine. I pressed the button and received two replies correctly. So please try this software first to see if the problem is caused by the serial debugging software.