How to mute and unmute a call on a Yealink T19P

You can mute the current call on a Yealink T19P so that the other party can not hear you. 

TO MUTE A CALL

During the call, press the  button

You will then see Mute displayed on the screen

TO UNMUTE A CALL

Press the  button again to unmute the call. You should no longer see Mute displayed on the LCD screen