Millions of people are using Nokia phones nowadays. Their hearing capacity also differs from one person to another and with that in mind many need to know how to adjust the sound of their phone. While pressing buttons, some people can adjust the volume. It is done very simply on a Nokia phone: all the user needs to do is press the + and - keys. It is a straightforward and very user-friendly procedure, typical of Nokia phones.
To increase/decrease the sound during telephone calls on a mobile phone, simply use the side buttons (+ or -)