There was no number system.

Every one was called by name.
Even as late as 1880, when New York boasted fifteen hundred telephones, names were still in use.

And as the first telephones were used both as transmitters and receivers, there was usually posted up a rule that was highly important: "Don't Talk with your Ear or Listen with your Mouth." To describe one of those early telephone exchanges in the silence of a printed page is a wholly impossible thing.

Nothing but a language of noise could convey the proper impression.

An editor who visited the Chicago exchange in 1879 said of it: "The racket is almost deafening.
Boys are rushing madly hither and thither, while others are putting in or taking out pegs from a central framework as if they were lunatics engaged in a game of fox and geese." In the same year E.J.Hall wrote from Buffalo that his exchange with twelve boys had become "a perfect Bedlam." By the clumsy methods of those days, from two to six boys were needed to handle each call.