Settings : Basic settings : Ringtones
Ringtones
Set the volume and melody for the ringtone and/or completely silence the ringtone for anonymous calls.
Volume
The volume of the ringtone for incoming calls can be set at 10 levels.
*    . . . use to select  Settings     OK    Audio Settings    OK    Ringtones    OK    Volume    OK . . .
the ringtone will be played with the melody set for external calls at the current volume; the volume is shown graphically.
* . . . use to select the required volume    Save
 
Changing the volume of the ringtone during an incoming call:
*Press the volume keys (for louder) or (for quieter)
Melody
Specify different ringtone melodies for different events (External Calls, Internal Calls,
Group Calls) and VoIP connections.
*    . . . use to select  Settings     OK    Audio Settings    OK    Ringtones    OK    Melodies    OK    . . . use to select event to be signalled with the melody    OK . . . the melody currently set for connection 1 is played    . . . use to select the melody required    if necessary, select melodies for the other connections    Save
Loading more ringtones onto the phone: Specifying and loading ringtones
Ringtone silencing for anonymous calls
Prevent the telephone ringing when no number is transmitted with an external call.
*    . . . use to select  Settings     OK    Audio Settings    OK    Ringtones    OK    Anonymous Call Silencing    Edit ( = the telephone does not ring for anonymous calls)