Remembering America's first social network: the landline telephone

Peter Amstein, a volunteer who serves as president of the Connections Museum board, says early phone technology shaped his IT career. (L. Tremaine)

As Peter Amstein squeezes through a warren of equipment racks draped with wire and crammed with whirring machines, he offers a cheerful warning.

"There are exposed electrical terminals, probably nothing will kill you," he says. "But there are definitely some things that will give you a fairly unpleasant zap, so do be a little cautious about what you touch."