The first commercial telephone exchange happened in New Haven, Connecticut, in 1878, courtesy of George Coy.
Alexander Graham Bell created the working telephone in 1875. While his company sold mostly to residents, it had to sell pairs and connect the two places. Then, George Coy obtained a franchise from Bell Company for New Haven, Connecticut. There he created the telephone switchboard.
The switchboard allowed companies to call an operator that would connect them to someone else. Now people did not have to buy a pair of phones, but only one. By the middle of February Coy and company published the first phone book with fifty names of people and companies that the switchboard could connect. Now we use our phones for video conferencing and classes.