There will be a few numbers, but none of them will be important for the purpose of this phone setup. One example will be the elevator line. In Pennsylvania, you must have a reachable telephone number that you would call from with the elevator line. There will be a dedicated number for such purpose, and will likely use a number I currently have already. I am sure you get the idea. The elevator line will likely be my current voicemail line since it had receive so little action, it will make the most sense for an elevator line.