Set the Volume on Samsung Galaxy S2

Call Volume

1. During a Call
2. Press the Volume Keys on the Left Hand Side of the device to adjust the call volume

Ringer Volume

1. Press the Volume Keys on the Left Hand Side of the device to adjust the ringer volume

Silent Mode

1. Press the Down Volume Key on the Left Hand Side of the device until it vibrates

OR

1. Tap Menu
2. Tap Settings
3. Tap Sound
4. Tap Silent Mode to toggle ON/OFF
5. Press the Home button to exit