Pls be more specific with this:
MD110 or MX-One?
Revision/version?
What do you really want to do? Hide the DEST number from the user?
Are you using LCR?
What is the trunk line type? Analog, MFC, ISDN? Private or public?
What is programmed on the key? TNS, ABB or what? Is there only the DEST number programmed, or the whole external number including DEST?
All this would help something for getting an answer, and this to start with....
fcpli