Possible response for Phil below also;
I have a TDM400P and have successfully implemented caller id using the lines shown at the top of this page.
However, I wanted to go one step further and change the ring type to UK, following instructions elsewhere on this site I changed the defaultzone and loadzone in zaptel.conf from US to UK. Sure enough the phones then rang with the UK style double ring but caller ID was lost...
Is there some sort of compatibility issue here, anyone know of a way around this?