If you have trouble hearing your phone ringing in noisy environments or calls are too loud, you can change the volume to your liking by using the volume keys on the side of your phone.
Do not connect to products that create an output signal, as this may damage the device. Do not connect any voltage source to the audio connector. If you connect an external device or headset, other than those approved for use with this device, to the audio connector, pay special attention to the volume levels.
To set the phone to silent, press and hold the volume down key and then press the key again. The first press sets the phone to vibrate only and the second press sets it to silent.