Acer M900 User Manual page 30

The video call screen
There are also several options available on the video call
screen.
Turn the camera on or off.
Switch from the front camera to the back camera.
Decrease screen brightness.
Increase screen brightness.
Mute the call.
Change the image layout, make your or your con-
tact's video the main picture, or view both videos
side-by-side.
End the call.
30 Acer M900 Smartphone User Guide