A panel at the building entrance where visitors select a unit and trigger an alert.

These use a phone line to call a resident’s designated phone number. The resident presses a specific key (typically 9 or 6 ) to trigger the door release.

The technology used depends largely on the age of the building:

Many DIY-oriented residents use external hardware to "smarten" old systems:

The hardware inside the unit—ranging from a simple button panel to a corded landline or a smartphone app—where residents receive the signal.

Modern systems like ButterflyMX utilize video calling and mobile apps, allowing residents to manage access remotely even when they aren't home. Automation & Smart Home Integration

An apartment door buzzer is an electronic access control system that allows residents to verify a visitor's identity and remotely unlock building entrances. While traditional systems use hardwired wall panels, modern versions often integrate with smartphones via cellular modules or internet-connected hubs. Core Components A standard buzzer system consists of three primary parts:

An electronically controlled latch that disengages when the resident "buzzes" the visitor in. Types of Buzzer Systems