By the time Bell and his wife returned to the United States at the end of 1878 the telephone was well on its way to becoming a big business. Never before had a revolutionary invention entered into commercial use so swiftly. The first central switchboard had been established in Boston (with boys as operators, until some inspired but forgotten genius discovered that girls were more polite). The first private line had been strung between Williams’ electrical workshop in Court Street and his home in Somerville, Massachusetts. Thereafter, with amazing rapidity wires wove steel traceries across the New England landscape and telephone poles sprouted like autumn weeds. Businessmen, lawyers, doctors, quickly discovered that, quite apart from efficiency and convenience, there was an element of status in owning a telephone. The first directory appeared in New Haven, with a list of fifty subscribers—among them the police department and the post office. And in Boston, Bell’s canny business managers, Hubbard and Sanders, supervised the manufacture and rental of telephone instruments, and girded up their loins for the first of an interminable series of legal battles in which the Bell associates would have to defend their basic patents against an army of predators. For it was becoming clear to electrical and telegraph companies that Bell Patent No. 174,465 was a valuable one. As events subsequently showed, it turned out to be the most valuable patent ever issued in the history of the U.S. Patent Office. By December of 1879, stock in the New England Telephone Company was selling at $995 a share.

Meanwhile Watson—chief technician in Bell’s absence—found himself confronted with the problem of devising a method of summoning people to the telephone. For some reason Bell had not thought of a bell.

It began to dawn on us [Watson recalled] that people engaged in getting their living in the ordinary walks of life couldn’t be expected to keep the telephone at their ear all the time waiting for a call, especially as it weighed ten pounds then and was as big as a small packing case, so it devolved on me to get up some sort of a call signal. Williams, on his line, used to call by thumping the diaphragm through the mouthpiece with the butt of a lead pencil. If there was someone close to the telephone at the other end, and it was very still, this worked pretty well, but it seriously damaged the vitals of the machine and therefore I decided it wasn’t really practical for the general public; besides, we might have to supply a pencil with every telephone . . . 

Then I rigged a little hammer inside the box with a button on the outside. When the button was thumped the hammer would hit the side of the diaphragm where it could not be damaged, the usual electrical transformation took place, and a much more modest but still unmistakable thump would issue from the telephone at the other end. . . .

But the exacting public wanted something better, and I devised the Watson “Buzzer”—the only practical use we ever made of the harmonic telegraph relics. Many of these were sent out. It was a vast improvement on the Watson “Thumper,” but it still didn’t take the popular fancy. It made a sound quite like the horseradish-grater automobile signal . . . and aroused just the same feeling of resentment. It brought me only a fleeting fame for I soon superseded it by a magneto-electric call bell that solved the problem, and was destined to make a long-suffering public turn cranks for the next fifteen years or so, as it never had before or ever will hereafter.

Watson solved another problem at this time which proved important in the future development of the telephone system. In his first version of the magneto call bell he had incorporated a manual switch that had to be thrown one way by hand when the telephone was being used, and then thrown back by hand when the call was terminated in order to put the bell back in circuit again.

But, Watson soon discovered, “the average man or woman wouldn’t do this more than half the time, and I was obliged to try a series of devices, which culminated in that remarkable achievement of the human brain—the automatic switch—that only demanded of the public that it should hang up the telephone after it got through talking. This the public learned to do quite well after a few years of practice.”