Calls repeatedly. If you answer with a business name, they hang up. If you allow it to go to vmail, the message says, "put a small sign in your yard, we will install a new security system at absolutely no cost to you. There is no cost for the installation or the system whatsoever. To hear more, Press 1. To be placed on a Do Not Call list, Press 9."
Of course, if you are lucky enough to actually HEAR the message and you Press 9, the system just hangs up on you so don't get your hopes up that the calls will end.