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 + or - (or the larger/smaller speaker icon) to adjust the ringer volume when the phone is on the idle screen.
2. Press + or - (or the larger/smaller speaker icon) to adjust the volume of the call when the phone is currently being used.