1. While on a call, to increase the volume press the Volume up key.
   
2. To decrese the volume press the Volume down key.
   
3. To mute a call, while on a call, tap the Mute icon.
   
4. The Mute icon will be displayed in the notification bar.
   
5. To unmute, tap the Mute icon again.
   
6. To turn on speakerphone, while on a call, tap the Speaker icon. 
   
7. The Speakerphone icon will be displayed in the notification bar.
   
8. To turn off speakerphone, tap the Speaker icon again.
   
9. To place the call on hold, tap the Hold icon.
   
10. To resume the call, tap the Unhold icon.
    
11. In the phone app, to show the keypad, tap the Keypad icon.
    
12. To hide the keypad, tap the keypad.
    
13. To access the home screen while on a call, tap the Home key.
    
14. To return to the call, tap the Phone icon.
    
15. Tap Return to call in progress.