Motorola configured the Droid 4 to vibrate whenever the smartphone is in silent mode so you will still be alerted to incoming calls. This limited vibration mode might be handy at times, but it can be disruptive in certain situations. The Droid can also be customized to always vibrate with alerts. To turn off vibration mode, you need to configure the Droid to never vibrate or restore the default setting so it only vibrates in silent mode. Writer Bio
