This came up before but perhaps things changed.
> I call, say Wilmington Delaware to Milwaukee, Wisconsin. How and who
> is the call physically routed and connected between the two cities?
> What about a shorter call, say Harrisburg PA to Erie PA (a few hundred > miles)?
> By how, I mean what physical medium is chosen and how is it routed.
> Do they use satellite, microwave, fibre optic, coax, plain wire?
"Yes". One or more of the above. _Probably_ fiber.
Are there direct routes or must it go to intermediate switching
> centers and transferred there?
The proverbial 'it depends'. On the specific locations involved.
Generally there are a number of intermediate centers involved.
What happens if the primary circuits are busy -- do they go to a
> lot of trouble to reroute or just cut me off?
Re-route/alternate route is _common_. "All circuits are busy, please try your call again later" generally indicates an issue *very*close* to one end or the other of the call.
Does AT&T still have a big network control center in Bedminster?
> Does anyone even have such control centers or are they not needed > anymore?
They're still needed. The nature of the beastie has changed considerably, over the years, however. Lots more 'smarts' in the hardware, allowing automation of much of what used to require 'manual intervention'. People are still required, for when the 'unexpected'/'unanticipated' occurs. automation doesn't deal well with things that it -hasn't- been programmed to handle.
By whom I mean does my designated long distance carrier actually
> physically carry the call or do they merely sublet to someone else who
> actually owns the wires to where I'm going.
"It depends." On _who_ the LD carrier is. Some have their own networks, some just buy 'wholesale' from those who do have their own physical infra- structure.
Who manages the switching centers?
Whomever owns the network involved.
I suspect a heck of a lot of long distance traffic is carried by
> someone other than the designated carrier.
Probably true. There are a lot more LD sellers than there are physical "national" networks.