Hey Altolabado.
FDN & HUNT will help you direct how an incoming call gets handled.
For example. If you have a user (1111) who wants his phone to ring on his secy (1112) but go to VMail (5555)if she's on the phone.. you can set this up to:
FDN 1112, HUNT 5555!
Keep in mind, All calls are routed to whatever is typed at FDN if unanswered.
If the FDN ext is busy, all calls are then sent to the HUNT.