A lot of people never realized just how much went through telephone exchanges besides regular phone calls.
I don't know about employees of the Bell System (or GTE etc.), but anyone working for the old GPO (General Post Office) telephones in Britain had to sign the "Official Secrets Act."
This was basically a sworn statement that you would not reveal to any third party anything overheard or intercepted during the course of your work on the equipment, under penalty of being confined in the Tower of London (well not quite
, but the penalties were five-digit fines and/or several years' possible jail time).
The central offices contained many leased lines of various types, for alarm control systems, private telex circuits between rather high-ranking officials, and so on.
When I was at an American TV station in 1995 we still had the old EBS system in place (I'm not sure, but I believe the system has now been replaced by something newer.) That two-tone signal that preceded the announcement was really quite dischordant and could almost have been designed to specifically give a feeling of impending doom! Fortunately, I never heard it followed by anything other than "This is a test of the emergency broadcast system..."
By the way, talking of the civil defense angle, have you seen that the "Duck & Cover" film with Bert the Turtle is available on-line to view?
[This message has been edited by pauluk (edited 05-24-2003).]