In the house I recently bought, built 1976 there is a 'phone' in the basement right next to the service panel. I call it a phone cause that is what it looks like, however, it doesn't have any numbers on it to dial with. When you pick it up there is no dial tone although we don't have land line service. What is really strange is when you pick it up and listen it seems as though you can hear faint echoing of what is happening upstairs. Has anyone seen one of these, or know what it might have been for ?