It is a reasonable question - almost every resident carries a mobile phone, so a gate that calls a mobile number sounds like it should cover the same job a wired intercom does. In practice, the two solve overlapping but different problems, and most societies that drop wired intercom entirely end up reintroducing some version of it within a couple of years.
The case against relying on mobile phones alone
A mobile-only gate depends on a specific number being current, the phone being charged and in range, and mobile signal being reliable at the exact moment someone is at the gate - none of which a society controls. A resident's number changes, a phone is on silent, a signal dead zone exists in exactly the stairwell where someone happens to be standing. Each of these is individually rare. Across a building with dozens of flats and years of operation, one of them happening at the wrong moment is not rare at all.
What a wired intercom actually solves
A wired intercom is tied to the flat, not to a person or a device. It works without mobile signal, does not depend on anyone's phone being charged, and does not go stale when a resident changes their number and forgets to update the society's records. For the specific job of “confirm who this visitor is before the gate opens,” a wired connection to the flat is a more dependable link than a mobile call, precisely because it has fewer points of failure.
Where mobile apps genuinely add value
Mobile apps and video door-phone-to-phone integration add real value for a different job: letting a resident answer the gate when they are not home, or seeing a live feed before deciding whether to buzz someone in. This is a genuine improvement over a purely wired system, which can only reach someone physically at the intercom handset inside the flat. The honest answer is that mobile extends what a wired system can do - it does not replace the reliability the wired link provides in the first place.
Running both without duplicating cost
Modern video door phone systems typically support both a wired handset in the flat and a mobile app extension from the same base unit, so this is not usually an either-or spending decision. Specify the wired intercom as the reliable baseline every flat has by default, and add mobile app access as an optional extension for residents who want it - rather than treating mobile as a cheaper substitute that quietly removes the baseline.
What to specify for a new or retrofit intercom
For a new building, run the wiring during construction, when it is close to free - retrofitting cable into finished walls is the expensive version of the same job. For an existing building without wired intercom, a retrofit is usually still possible along existing conduit or cable routes if a survey confirms them, and can often be phased in alongside a broader video door phone upgrade rather than run as its own separate project.
Common questions
Can we retrofit wired intercom into an older building without major disruption?
Often, yes, if existing conduit or cable routes can be reused - this needs a physical inspection to confirm, similar to any CCTV cabling upgrade. Where routes genuinely do not exist, it becomes a larger job, and we will tell you honestly which case you are in before quoting.
Does a mobile app replace the need for a physical handset?
Not entirely - a handset works without a phone, a data connection or a charged battery, which matters more than it sounds during exactly the situations where you need it most. We recommend the handset as the reliable default with the app as an added convenience, not a full replacement.
Is EPABX the same thing as intercom?
They are related but distinct - EPABX is the underlying telephone exchange technology that can run an intercom system, particularly useful where a site needs to connect many extensions, including gate, guard room and every flat or floor, on one internal network. For a factory version of this question, see our guide on EPABX for factories.