The N73 is a 3G-network-compatible smart phone from Nokia. It runs using the Symbian operating system. As you can with most cellular telephones, the Nokia N73 allows you to decrease and increase the volume of calls at will. This is accomplished through the volume control buttons that are built into the side of the unit's case, near the battery charger input and other secondary buttons.
Turn on your Nokia N73.
Press the "Volume Up" button on the side of the Nokia N73. An on-screen volume indicator will appear on the N73's screen, indicating that the volume has been increased by one "bar."
Press the "Volume Up" button on the side of your Nokia N73 button again until the on-screen display indicates that you've increased the volume of the unit to match your personal preferences.