A visitor presses a button outside a block of flats. Inside, a resident asks who is there and releases the lock. It is a modest exchange, but it asks the building to solve several problems at once: recognise a visitor, let the right person in, protect everyone else and make sure nobody is trapped if something fails.
The familiar buzzer now competes with video panels, phone apps, temporary access codes and cloud-based logs. Each can be useful. Each also adds a question. An intercom is not simply a screen attached to a door; it is part of the building's access policy.
From voice to video to phone
A conventional audio system carries a conversation from entrance panel to indoor handset. A video version adds a camera so the resident can see the person waiting. Internet-connected systems may send the call to a phone, allowing a resident to answer while away, or allow a manager to issue time-limited credentials. These are design choices, not automatic upgrades.
Video can help distinguish a delivery from an unexpected caller, but a camera does not establish identity perfectly. Coats, darkness, camera angle and a borrowed uniform can all confuse the picture. Nor does answering remotely guarantee that a parcel can be safely received. The most dependable system makes the action clear: whom am I admitting, to which space and for how long?
Remote access can be valuable to someone who has limited mobility or is expecting a carer. A temporary code can avoid leaving a key in an insecure place. Yet sharing codes casually can turn convenience into a lasting access route. Building managers need to know who issues credentials, how they expire and how a lost phone or departing resident is handled.
A camera points both ways
A camera at a doorway may record residents, visitors and passers-by who have not chosen to use the system. The Information Commissioner's Office explains that smart doorbells capturing communal or public areas can bring data protection obligations into play.¹ A block-wide intercom raises additional questions about who can view footage, how long it is kept and whether it is used only for the stated purpose.
The simplest privacy improvement can be physical: aim a camera at the entrance, not a neighbour's window. Limit access to recordings, avoid keeping them indefinitely and tell people what is being collected. A video feed that automatically uploads every encounter to a distant service is a different proposition from a live view on a local handset. Residents deserve to understand that distinction before installation.
More features also mean more software. The UK's product security rules, in force since April 2024, require basic safeguards for consumer connectable products, including rules on default passwords, vulnerability reporting and information about the minimum security-update period.² Those requirements are a starting point, not proof that every installed system will remain secure forever. A device that controls a door needs a maintenance plan as well as a glossy launch.
NIST's guidance on connected devices emphasises security capabilities across a device's life cycle and the systems with which it interacts.³ In practice, the weakest point might be an unpatched panel, a shared administrator account or a phone that still holds access after its owner moves out. Physical keys have their own weaknesses, but software access needs the same disciplined housekeeping as a key cabinet.
The visitor who cannot use it
An entrance that only works through a smartphone can exclude someone without one, a visitor whose battery is flat or a person who cannot manage its interface. An audio-only panel can fail a deaf visitor; a screen with tiny text can fail someone with impaired sight. The current Approved Document M guidance for buildings in England explicitly addresses accessibility of door-entry systems, including people who are deaf or hard of hearing and people who cannot speak.⁴
Accessibility is not an optional extra installed after a complaint. It affects button height, contrast, lighting, feedback and the time a door stays open. A caretaker carrying a box, a child accompanying a parent and a wheelchair user may all need more than a hurried few seconds after the buzzer sounds. Different buildings have different legal requirements, but the underlying question is universal: can the visitor complete the journey from pavement to destination?
A shared entrance adds governance as well as engineering. One resident may want every caller recorded; another may not want their daily movements visible to a neighbours' committee. A building needs rules for complaints, access requests and changing permissions when residents move. Technology cannot decide those rules for the people who live behind the door.
When the connection fails
An app may depend on an internet connection, cloud service and charged devices. That creates several opportunities for failure. A sensible design asks what happens during a power cut, a network outage or a supplier's closure. Can residents still reach home? Can emergency services and authorised staff get in? Can occupants leave safely?
Fire-safety guidance distinguishes access control from exit control and stresses adequate means of escape where electronic locks are used.⁵ A system that refuses to open from outside during an outage is inconvenient; one that obstructs safe exit can be dangerous. These questions require building-specific assessment rather than a generic product promise.
The future of the intercom may include better cameras and cleverer credentials, but its success will be judged in ordinary moments: a visitor can make contact, a resident can decide, a person with a disability is not stranded, and the door behaves predictably when the network does not. That is innovation worth hearing through the speaker.