I have a customer with a door intercom unit, from what I can tell it's a push button and looks like a speaker in it. (have not taken off to see yet)

Is there a way to hook up to Axxent through a loop start port so when someone pushes the button it rings phones?
What do I need in between, called Bogen tech and he swears there is nothing they sell to do that. I swear I have seen this before?