You can press the Volume key to adjust the receiver volume of currently used audio devices (handset, speakerphone or headset), when the phone is in the dialing interface or during a call. You can also press the Volume key to adjust the ringer volume when the phone is idle. 

To adjust the volume: 

1. Press  to adjust the ringer volume when the phone is in the idle screen.  

2. When the phone is during a call, press  to adjust the volume of currently used audio device (handset, speakerphone or headset).