Open My Computer and Dial Up Networking and create a new connectoid (if you don't have one yet). Then double click the connectoid, and hit the "Dial Properties" button.
This gets you into a manager for different "locations" your laptop might be in. You might have one of these for campus, for example, that has "always dial 9 to get off campus" set. You might have a different one for home. In this panel there will be an "always dial as" radio group. If you set "long distance" then the current country code (1) and area code (301) will be prepended to the phone number in the connectoid. Thus, it will dial 1-301-209-0700 for you. If you make a separate campus "location" you can make it dial 9-1-301-209-0700 instead. Don't forget to set the "9" in both the local and long distance boxes.
AFAICD from both my documentation and extensive playing around this is the only way to get to the locations database...