Acer Iconia Talk S A1-724 - Manual (Page 39)

Acer Touch WakeApp - 39
Double-tap gesture
Double-tap the screen with a finger to wake your tablet and
launch the assigned app.
If your tablet is locked...
If your tablet is locked, for example by using a PIN, facial recognition,
or a pattern, you will be required to perform the unlock action after
using any of the gestures. Once you have unlocked the tablet, the
screen will be rotated as necessary and then the app assigned to the
gesture will launch.