1200 Third Avenue

1200 Third Avenue is the building originally owned by Pacific Telephone and Telegraph which housed telegraph and Teletype equipment that served the Seattle area. This equipment includes the No. 9 Telegraph Testboard and the 2B Electronic Hub Teletype Testboard (which replaced the No. 9) currently on display in the Connections Museum's Teletype collection.

Apple Maps street view of the old "Main" building at 1200 3rd Ave.

It was eventually replaced after the construction of "new" main at 1122 Third Avenue.