Fine, fine - a dialog is fine. People have all sort of levels of background or knowledge here 
sometimes the level presumed is wrong.
"Connect through a port" isnt informative enough, sorry. Serial port, USB port, IEE488 port, Firewire?
Here is my "vision" of the problem so far, and where the Arduino goes. Now and Later, respectivly:
 NoteBook -------(port?)------- DIC (+some valvestuff)
 NB --(USB)-- Arduino ---(?)--- DIC (+samevalves)
The connection or "port" used on the DIC may be different in the two cases, if possible or convinient.