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How do I Set my T-Mobile Samsung SGH-t159 to Silent/Vibrate Mode?
You can set the Silent/Vibrate mode on your device by following the instructions below.
To quickly set your device to vibrate only, from the Home screen, press and hold for one to two seconds until you see the Vibration profile on message displayed on the screen. When activated, the icon will appear in the status bar at the top of the screen. To return to a previous profile, press and hold the key again.
To set your device to the Silent profile, press the Volume down key on the side of your device until you see the icon.