To send press and hold the button with the left mouse or use the space bar (on the keyboard).
Vu is the recording level indicator for the microphone entrance of the sound map. With the volume controller (Vol) the desired microphone volume can be adjusted. It must be paid attention to the fact that the recording level indicator goes to no time into the red range, because this becomes apparent during the speech transmission otherwise as scratching noises. The volume controller has an ALC (Automatic Level Controll), that means, if the level is to high, the level automaticly goes down.
Vu is the recording level indicator for the loudspeaker exit of the sound map. With the volume controller (Vol) the desired volume can be adjusted.