How did ‘Hello’ come to be used as a greeting over the phone?

The first word used to answer the phone was the nautical greeting “ahoy” because the first regular phone system was in the maritime state of Connecticut. Alexander Graham Bell, the inventor, answered with the Gaelic “hoy”. But it was Thomas Edison’s greeting of “hello,” an exclamation of surprise dating back to the Middle Ages, that caught on, and so we answer the telephone today with, “Hello?”