When answering a call, should we say AHOY or HELLO?

"Ahoy, Monty! Are you there? Say something, dammit!" 

We are supposed to say something when we answer a phone call since remaining silent is not a smart option. It is also logical to say HELLO because as an item HELLO is conveniently short and not too formal or informal. Therefore HELLO is perfect in that sense, otherwise it would not have endured for so long.

Still, the question remains: Why HELLO precisely? Who came up with that idea?

Amazingly enough, it was not the inventor of the Telephone, Alexander Graham Bell. For him the best option was "Ahoy!" How did he come up with that idea? AHOY is the way sailors greet each other, and HELLO was not at the time (the 1870s) a standard greeting yet. HELLO was used the way we use HEY in our days.
It was none other thanThomas Alva Edison, the inventor of the Lightbulb, who suggested to use HELLO instead of AHOY, and that was the beginning. In fact, the use of HELLO became so popular afterwards that people began using it in situations other than phone conversations and that is how it became a common greeting. 

In Spanish we say ALÓ which is obviously derived from HELLO (pronounced HULLO). 

These days no one uses AHOY when answering a call save perhaps Monty Burns from The Simpsons. But he is that old.