SEN0539-EN turn off voice responses

Dial the code to the SPK2 side, at the same time SPK2 interface do not external speakers will not have voice prompts.

use the mute function ==   set_mute_mode(1) with i2c connection and  similar with uart/serial   setting_CMD( 0x83, 1) ==  that will also shorted the dead time. 
Just switching the speaker to external, will block the mic input until the response phrase is finished.

The API has a command to setMuteMode

Hi, apparently if you don't have a speaker connected to speaker 2 then putting the switch in that position makes it quiet.  If you do have a speaker 2 connected then I'm sorry, someone more experienced will have to advise.