Doug,
Nice find by the bride. Those display phones were sure impressive back in the mid 80s. I have one stored away somewhere..."sorta" recall mine was made in Mexico . When I was done with a DMS 100 /remote installation I was given one. I actually used it for packet radio (data over ham radio) used the modem at 900 baud ...about as fast and functional as an electric can opener.
Northern had a very large presence in Raleigh , North Carolina at Research Triangle park. Their training center and Network HQ was there. Vaguely remember somewhere else , maybe Durham they did have a factory or assembly unit. Spent months and months at their training center.
Doug you probably know that in New England Tel ...ALL switching equipment was installed by New England Employees ( EI Dept )Not Northern , WECo. , Nippon ,or Seimens et al .
So I lucked out and enjoyed lots of time in Raleigh for training.
Andy F