What ring tones can I set for callers to hear?

You can set the country/ nationality of the ringing tone, which is set to default to the UK ring tone. 

You can set it so that music is played instead of a ring tone, which takes precedence over the ring tone nationality if both are set. 

You can also set WHEN to generate a ring tone, as a for instance' until destination starts ringing' or 'until destination is answered'.