In general FreshBuzzer works in all buildings that have a phone based intercom system - unfortunately not the hardwired phones, but anywhere where a phone number is involved.

Additionally many intercoms restrict calls to local phone numbers. While FreshBuzzer always gives you local phone numbers it is A) not always possible to determine local calling without knowing the building's phone number and B) there are areas where our phone service provider might not have any local phone numbers available.