The one is a supplement to the other.

The post office sends a package; the telegraph sends the contents of the package; but the telephone sends nothing.

It is an apparatus that makes conversation possible between two separated people.
Each of the three has a distinct field of its own, so that there has never been any cause for jealousy among them.
To make the telephone an annex of the post office or the telegraph has become absurd.

There are now in the whole world very nearly as many messages sent by telephone as by letter; and there are THIRTY-TWO TIMES as many telephone calls as telegrams.

In the United States, the telephone has grown to be the big brother of the telegraph.