Mine sounds as close to a real phone as possible.
I use the Galaga intro theme. Except the one I have starts off with the sound of the credit/quarter being inserted.http://www.geekrant.org/files/2006/galaga-ring.mp3
Adding PCE console specific layer on top of that, makes for an interesting challenge (no, not a reference to Ys II).
I should've expected that from you Razz .
I have robos theme from chronotrigger