HTC One User Manual page 48

48 Your first week with your new phone
Pick up to lower volume
Increase ring volume automatically while phone is in your pocket
or bag
In a business meeting or restaurant,
pick HTC One up when a call comes
in to lower the ring volume
automatically.
You can turn this feature on or off.
Go to Settings, tap Sound, and then
select or clear Quiet ring on pickup.
Pocket mode makes HTC One recognize when
your phone is in your bag or pocket and raise the
ring volume so that you can hear it in noisy
environments.
You can turn this feature on or off. Go to Settings,
tap Sound, and then select or clear Pocket mode.