If there had been at first two separate companies, one owning the telephone and the other the switchboard, neither could have done the business.
Several years before the telephone got a switchboard of its own, it made use of the boards that had been designed for the telegraph.

These were as simple as wheelbarrows, and became absurdly inadequate as soon as the telephone business began to grow.

Then there came adaptations by the dozen.

Every telephone manager became by compulsion an inventor.

There was no source of information and each exchange did the best it could.
Hundreds of patents were taken out.