Changing Sound Settings - HTC Verizon windows phone 8X User Manual

Setting the time delay before the screen turns off
After a period of inactivity, the screen turns off automatically to save
battery power. You can set the idle time before the screen turns off.
1. On the Start screen, slide to the left.
2. Tap Settings > lock screen.
3. Tap Screen times out after, and then select the time length that you
want.

Changing sound settings

Setting your phone to silent mode
When you keep pressing the VOLUME DOWN button until the volume level
reaches zero, this makes your phone vibrate only. To be able to switch
your phone to silent mode using the VOLUME DOWN button, you need to
turn vibrate off in the settings.
1. On the Start screen, slide to the left.
2. Tap Settings > ringtones+sounds.
3. Tap the Vibrate On/Off switch to turn vibrate off.
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