In 1875, Charles Williams, Jr. was a successful businessman who manufactured telegraph instruments. He would shortly become a different kind of manufacturer and an even more successful businessman.
In June of that year, Alexander Graham Bell and his assistant Thomas A. Watson - who had been using Williams’ shop on Court Street to experiment with a device called a telephone - would succeed in transmitting sound for the first time.
Williams bought the house at 1 Arlington Street in Somerville a year later. The first permanent residential telephone line in the world was installed in the home in 1877 and connected the Williams home to his shop in Boston. These would be numbers 1 and 2 in the Bell Telephone Company network.
Thomas Watson soon gave Williams a production order for 25 box and 50 hand telephones. It would not be the last. Williams could barely keep up with demand for these new devices - by August of 1877, 778 telephones were in operation and his shop was churning out 50 a day. A formal agreement between the patent holders and Williams in 1878 gave Williams exclusive rights of manufacture, with Watson serving as quality control. This was the beginning of the American Bell Telephone Company, which would later evolve into an entity called the American Telephone & Telegraph Company (or as you probably it, AT&T).