GSM & 4G Door Entry Systems

A GSM intercom is a door or gate entry panel with a SIM card inside. When a visitor presses the button, the panel doesn't ring a handset on the wall — it makes a phone call over the mobile network to whatever numbers you choose. You answer on your mobile, speak to the visitor, and press a key on your phone to release the door or gate. If you don't pick up, the call diverts to the next number on the list.

That one design decision solves the problem that rules out traditional door entry on so many sites: cabling. A hard-wired intercom needs a cable run from the entrance to every handset, and often a phone line too. On a gated driveway, a farm entrance, a commercial yard or a block of flats being retrofitted, that cabling is disruptive, expensive or simply impossible. A GSM intercom system needs only two things at the entrance — power and mobile signal — which is why it belongs in SEG's remote connectivity family alongside our 4G-connected CCTV and ANPR services.

The second advantage is that you are no longer tied to a handset. A wired intercom only helps if someone is standing near it; a SIM card intercom reaches you wherever you are. Deliveries arrive while you're out, contractors turn up early, tenants lose fobs — with GSM and 4G door entry you take the call, verify the visitor and let them in from the office, the tractor cab or the beach. Security & Electrical Group Ltd supplies, installs and supports these systems across England, with the SIM and call plan managed by us as one monthly service.

Voice gets the job done, but sometimes you need to see who's there before you open up. A GSM video intercom — more precisely, a 4G door entry system — uses a mobile data connection instead of a voice call. The panel has a built-in camera, and when a visitor presses the button it places a video call to an app on your smartphone. You see the visitor, speak to them, and unlock the door or gate from the app, wherever you happen to be. The app keeps an event log of every call, answer and release, and many panels capture a snapshot of each visitor even when the call goes unanswered.

Choosing between voice-only GSM and 4G video comes down to what you need to know before you press unlock. For a family home gate where you recognise every caller's voice, a GSM intercom with voice calling is simple, cheap to run and works with any phone — no app, no smartphone required, which also suits older residents. Where you're screening unknown visitors — commercial yards after hours, high-value residential property, managed buildings — a 4G intercom with video is worth the slightly higher data cost, because seeing the caller and keeping a visual record changes the security picture entirely.

Both run on a managed SIM supplied by SEG. For video systems we size the data plan to intercom traffic — short video calls and snapshots are light, efficient machine data, which is exactly what our managed connectivity service is built around.

Multi-tenant door entry is where GSM makes retrofits practical. A conventional flat intercom needs a wiring riser from the front door to a handset in every flat — straightforward in a new build, miserable in an occupied Victorian conversion. A multi-button or digital-directory GSM panel replaces all of that: the visitor presses the button (or scrolls to the name) for flat 4, and the panel calls the mobile of whoever lives there. Each flat answers on their own phone and releases the door with a keypress. No riser, no handsets, no decorating bills, and residents can answer the door from the sofa or from work alike.

For managing agents and landlords, the day-to-day running is the real win. Tenants change, and with them their phone numbers — on a GSM door entry system that's a remote reprogramming job we do from our office, usually the same day, rather than an engineer visit or a new handset. Directory names update the same way. Trade buttons, postal access codes and time-restricted entry for cleaners are all standard features, and the panel keeps working through building works that would sever a wired system.

SEG installs multi-tenant GSM panels on blocks from four flats to forty-plus, for freeholders, managing agents and housing providers, with the SIM, call plan and all number changes wrapped into one predictable monthly service per building.