Even mildly sensitive phonecalls do not get made anywhere near a window and anything down to mundane items like laser printers and photocopiers are either imported from a secure source or if they are bought locally they are examined back to front to make sure they haven't been interfered with.
Given what we know about the US government, I think I'd have more faith in a laser printer bought from Walmart than one imported from a "secure" source.
"We don't care. We don't have to. We're the Phone Company."