I have been looking to lose my landline and go wireless for some time now. The problem is that in my building, the main door rings through my phone and I need to press a button to let them in. When I tried to inquire as to whether I can use a smartphone to handle this operation I get a clear "don't know" from both the property manager and the company that makes the door system. I am finding this frustrating and it is the one think chaining me to the last century. Do you live in a place with a door buzzer? Are you able to use your smart phone to buzz people into your building?