Why is my phone number needed for the doorbell to ring upstairs?

I am moving into a new building, and was recently informed that all tenants must provide their phone numbers to have an active doorbell. I've never heard of this before? But then I've always lived in older buildings. Can someone explain how this works, and why management offices are doing this? What happens if your phone service is disconnected for non-payment and turned back on? Will management have to reprogram everything again?

Does this mean the bell doesn't ring at all? Only the phone? Does this mean all visitors must have my phone number? I don't give all my relatives my home number? lol

Also, when someone rings the bell, will caller ID let me know whether it's the door or a call? Sometimes all this high tech stuff just takes away from privacy.

in some places when the bell is rung outside it rings on your home phone.

They have a security system that requires a visitor to dial a number into a system from a phone in the lobby or vestibule to gain entrance to the building. Depending on the number of units in the building the visitor is required to dial a one, two, or three Etc.. digit number corresponding to your unit. Your phone has a special ring to let you know someone is at the door. You answer the phone to find out who is at the door and what they want. You then can decide if you want to "buzz them in" by activating the remote lock on the entrance door. Some systems even have a video hookup that you can see the entrance and who is there.