You ditched your landline years ago. Smart! Because the one thing it was good at—buzzing people into your building—can be done better with your smartphone anyway. Here's how to have that buzzer ring any phone you want.
First, you'll need a Google Voice account. If you already have one, you're halfway there. If you don't have an account, here's a handy guide on how to get one. Once you've got a Google Voice number, give it to your landlord/super to program into your building's buzzer system. Now the when someone rings your apartment buzzer, the call will be routed to the Google Voice account.