Getting your buzzer to ring more than one phone

Almost every apartment intercom holds one phone number per unit. These are the ways around that, what each one costs, and which ones actually work.

How to Make Your Buzzer Ring Everyone in the Apartment
One buzz, and every phone in the apartment rings at the same time. What to change, what to hand your building, and where the free routes fall short.
9 min read
How to add more than one phone number to an apartment buzzer
Your building stores one phone number per unit. Here is the one approach that rings everyone at once, the four cheaper routes, and exactly where each of them breaks.
9 min read
How to add a roommate to your apartment buzzer
The building can only store one number, so adding a roommate means changing what that number rings. Four ways to do it, and what each costs.
5 min read
Can an apartment buzzer ring two phones at once?
Not from the lobby panel, which dials one number. But you can point that number at something that rings two phones together. Here is the difference that matters.
5 min read