In 1908, virtually all telephones still used human operators, who manually connected lines together at a central switchboard at the individual requests of their subscribers, no matter what their age. (The title of this article comes from a long-time advertising slogan for Fletcher's Castoria laxative).
Telephony, March, 1908, page 177:

A BUSY Lawrencian recently added a telephone to the modern improvements at his home, says the Lawrence (Mass.) Tribune. He has four happy children, all of them young, to whom the telephone was new and who regarded it with awe. One of the kids is a boy of four. He watched the older people call up "Central" and communicate with friends at distant points and yearned to do likewise.
    His mother chanced to be absent from home for an hour or so on a recent afternoon. The other children were out somewhere. He was alone. For a half hour he watched the telephone, then climbed up and took the receiver of the telephone off the hook just as he had seen older people do. By this time he was trembling, but his courage was as strong as chilled steel.
    "Number?" he heard a sweet voice inquire. For a moment he was startled, but he conquered a desire to drop the receiver and run and shouted bravely, "I want my pop!"
    "Central" must have recognized the voice as that of a child. She promptly inquired, "Who is your papa?"
    The little fellow knew enough to tell her, and it was but a matter of a few moments to ascertain the number of the busy Lawrencian's business telephone and connect the four-year-old.
    "Hello?" answered the busy citizen, turning away from a desk overburdened, with papers and things.
    "Oh, pop, I kin work it!" was the joyful little shout that answered him, and the busy citizen was just as proud and as pleased as the four-year-old at the other end of the line when the brief conversation ceased and the boy, obeying instructions given over the wire, hung up the receiver and awaited the home-coming of mamma to tell her of his conquest.