How does landline telephone work across the ocean?

Firstly I recommend the following article which is a few years old but which really gives a great insight into how sub-sea cables work and are laid. read more

The short answer is that cables carrying telephone wires were laid down on the ocean floor, as early as 1956. Transatlantic telegraph cables started being laid in 1858. The Wikipedia article Transatlantic communications cable lists quite a few public and private cables. read more

You are kind of right about the 'telephone poles in the ocean', except there are no poles. There are literally dozens and dozens of fiber optic cables that have been installed over thousands of miles across the ocean floor all over the world connecting all of the continents together. read more

The easiest solution was that the phone exchange provided enough current to ring the bell on the telephone by sending an AC voltage signal down the line. In simple terms this AC signal causes some electromagnets in the phone to move and that rang the bell. read more