They can flip a switch from the spook room to monitor central switches, however that requires subsequent processing by “big data” software to ferret out the traffic in question.
To avoid that processing they can be more direct by placing equipment closer to the source.
Anything transmitted outside the building any appreciable distance, like a cell phone call, is already slurped up by the NSA due to their signals intelligence function. Requires same data processing.
“They can flip a switch from the spook room to monitor central switches, however that requires subsequent processing from “big data” software...”
True story: in the weeks following 9/11, there was much talk of ‘young middle eastern men’ fitting the terrorist profile.
I was talking on the phone with my nephew, a military guy. Was telling him about a young engineering student I’d known awhile back, who was the son of one of Gaddafi’s honchos.
Right when I said “Gaddafi” the phone went dead.
Nephew calls me back, we resumed conversation. As soon as I said “Gaddafi” the phone goes dead again.
I try to call him back, but the phone stays dead for twenty minutes.
Finally we reconnect. He’s laughing.
He says, “Whatever you do, don’t say ‘Gaddafi.’”
Bam! Dead again!
We realized we were being monitored by that NSA software that’s programmed to “grab” certain words and examine the context.
So this became our greeting whenever we see each other at Thanksgiving:
“Gaddafi!”
“Don’t say Gaddafi!”
“Gaddafi!”
It's possible the NSA slurps up and saves everything but doesn't have the time to look at it unless there is some interest. A "wire tap" would be nothing more than searching years of data capture they already have.