Vodafone 155
Find "Ringtone"
Press the Navigation key.
Scroll to Settings and press the Navigation key.
Scroll to Sound and press the Navigation key.
Scroll to Volume and press the Navigation key.
Scroll to Ringtone and press the Navigation key.
Adjust ring volume
Press Navigation key up or Navigation down to adjust the ring volume.
Save and exit
Press the Navigation key to save.
Press Disconnect several times to return to standby mode.