A message for today from last century's vast telephone exchanges

I STOOD inside a warehouse, sandwiched between two floor-to-ceiling frames that looked like ancient bookshelves or perhaps server racks from another planet. Their surfaces were alive with chattering metal switches attached to wires so old their plastic sleeves had faded to brown. It felt like I was trapped in a machine from a Charlie Chaplin movie. But I was actually in the guts of a Number Five Crossbar Switching System (5XB), developed at Bell Labs during the 1940s to route thousands of phone calls at once. The sounds I heard were numbers cascading through electrical switches mounted on crossbars, establishing …