Edison was apparently quite successful, to the point where some languages other than English have a word that sounds like “hello” (for example, Russian “allo”) which is used only when answering the phone.

Just as the ducks at the park are free, there is also no legal requirement to answer the phone in particular way. Hit folks with a, “Ahoyhoy”, “Howdy”, “Whats good brother?”, or for the more adventurous, “Ralphs Roadkill Cafe. You kill it, we grill it.”