I live in an apartment complex that has a call box at the front door (where visitors can type in my apartment number & it will call up to my phone and I can press the # button to open the front door). In order for this to work though, I need a land line. As I understand it, Magic Jack plugs into your modem, NOT the actual phone jack in the wall. So my question is, if I get Magic Jack, will visitors be aable to call me from the call box even though its plugged into my moden, not the wall. Because I hate to pay $30+ a month for a phone line I will ONLY use for the call box, when Magic Jack is $20 a year.