Today in 1894, New England Telephone and Telegraph installed the first battery-operated switchboard in Lexington, Massachusetts. With what became to be known as the “common battery” (replacing the local battery attached to the telephone), the subscriber could signal the operator simply by lifting the receiver from its hook. According to the 1911 edition of the Encyclopaedia Britannica, with this development, “the time occupied by an operator per call was reduced from 50.77 seconds to 16.63 seconds.”

By the way, the 1911 edition also tells us that the term “telephony” was first used 150 years ago by Philipp Reis of Friedrichsdorf, in a lecture delivered before the Physical Society of Frankfurt.