The telephone and the switched network

On 10 March 1876 Alexander Graham Bell wrote in his notebook that he had spoken into his apparatus, “Mr. Watson — come here — I want to see you”, and that Thomas Watson, in the next room, had come.

One telephone wired to another is a curiosity. To be useful, every phone has to be able to reach every other, and wiring each pair together directly is impossible beyond a handful of homes. The answer was a place in the middle where lines could be connected on demand: the exchange.