While the phone is connected to a call you can adjust the volume. The volume that gets adjusted will depend on whether you are using the handset, speakerphone or headset at the time you use this process.

To adjust the call volume: (1403/1408/1416)

1.Use the up arrow up arrow and down arrow down arrow keys to change the volume. On 1403 phones use the – key volume + rocker button to adjust the volume.