See also:

Models with Hands-free system
Press this button for more than 1.5 seconds if you wish to immediately cut the volume to zero. The audio display will show “MUTE”. If you press the button for more than 1.5 seconds again, the origin ...

Volume control
Volume control You can adjust the phone call volume, the voice volume and the voice guidance volume. Refer to “Volume control buttons”. ...

Tone and balance control (type A, B and C audio)
Each brief press of the “TUNE/TRACK/ CH” dial changes the control modes in the following sequence. Choose the preferred level for each mode by turning the “TUNE/TRACK/CH” dial. The control ...