All the talk about the mid 60s Get Smart phone suddenly jarred my memory with respect to something I hadn't thought about in decades. Perhaps someone can clarify it.
In that era, I earned some money as a teenager by working as a delivery boy at a local pharmacy. I recall that at the close of business, they needed a way of having after-hours calls reach a human. The pharmacist would throw a switch on the wall (and for some reason I want to think it was a knife switch, but that might be my vivid imagination) and the incoming line to the pharmacy would now be directed to his home a mile or so away.
This was in suburban Philadelphia.
What sort of technology are we talking about here?
Art