IP Intercom & Video Door Entry Systems: Modernising Building Access for Commercial Properties

The front door of a commercial building communicates two messages simultaneously: it welcomes authorised visitors and it controls access for everyone else. The technology at that door — whether a buzzer with a grainy camera, a standard desk phone, or a modern IP video intercom — determines both the visitor experience and the security effectiveness of your entry point.

Bangladesh's commercial building sector is in the middle of a transition from analog door entry systems — installed a decade ago with poor audio quality, worse video, and no integration capability — to IP-based video intercom systems that connect to your existing data network, display HD video on any screen (including smartphones), integrate with access control systems to release door locks automatically, and use the SIP protocol to deliver intercom calls to standard IP desk phones or softphone apps.

This guide explains how IP video intercoms work, what SIP-based architecture means in practice, and how they integrate with the rest of your building security and communications infrastructure.

IP Video Intercom vs. Analogue Door Entry: The Key Differences

Traditional Analog Door Entry

Traditional door entry systems use dedicated wiring: a two-wire bus connecting the door panel (with its camera, microphone, and call button) to indoor stations (monitors or handsets) inside the building. Each indoor station is typically wired directly to the door panel or to a switching unit.

The limitations of analog systems are significant:

• Limited scalability: Adding more indoor stations or door panels requires additional dedicated wiring runs.
• Low video quality: Analog cameras at the door panel provide QVGA or VGA resolution — barely adequate for identifying visitors, and clearly inadequate for capturing video evidence of security incidents.
• No remote access: Calls from the door panel reach only the indoor stations physically wired to it. There is no way to answer a door intercom call from a smartphone or a PC.
• No integration: The intercom system is a closed island — it cannot communicate with the access control system, the security management software, or the IP phone system without complex and expensive interfacing hardware.
• Geographic limitation: In a multi-building complex, an analog door panel can only call indoor stations in the same wired network. Cross-building intercom requires separate infrastructure or complex bridging.

IP Video Intercom: Network-Based, Feature-Rich

An IP video intercom operates over standard Ethernet (the same network infrastructure your computers and IP phones use). The door panel — called the door station — has an Ethernet port, an IP address, an HD camera (typically 1080p or 2MP), a microphone, a speaker, and buttons. The indoor station — a monitor unit, an IP desk phone, a smartphone app, or a software client on a PC — receives the intercom call as an IP communication event.

This network-based architecture changes the capabilities fundamentally:

• Any IP device can be a station: An IP desk phone (Fanvil, Yealink) in any office, a tablet in the reception, a smartphone anywhere in the world — all can receive and answer door intercom calls.
• HD video: The door station's 1080p camera sends live video to the indoor station during the call. The person answering the intercom sees the visitor clearly before deciding to release the door.
• Remote answering: A building manager at a branch office can answer an intercom call from your main office door station — over the internet — and remotely release the door lock, all from a smartphone app.
• Integration with access control: The door station has a relay output that triggers the door strike or electromagnetic lock directly. Or it sends a signal to the access control system, which makes the access decision based on time schedules and permission rules.
• Scalability: Adding more door stations or indoor stations is a matter of IP configuration, not new cable runs. A 50-door intercom system on an IP network uses the same infrastructure as a 5-door system.

SIP-Based Intercom: Integration with Your IP Phone System

The most powerful capability of modern IP intercoms is SIP compliance. SIP (Session Initiation Protocol) is the standard protocol for VoIP telephony — the same protocol used by IP desk phones, softphones, and IP PBX systems.

When a door station is SIP-compliant, it registers with your IP PBX (Grandstream UCM, Yeastar, 3CX, or any other SIP server) as a standard extension. When a visitor presses the call button, the door station initiates a SIP call — exactly like an IP phone call — to one or more destination extensions.

The destination can be:

• A specific IP desk phone at the reception desk (the visitor presses the "Reception" button and rings the receptionist's phone)
• A ring group (the call rings the reception desk and two backup phones simultaneously; the first to answer handles the visitor)
• An IVR/auto-attendant (the visitor hears a menu: "Press 1 for Sales, Press 2 for Accounts")
• A softphone app on the receptionist's smartphone (the receptionist answers from the cafeteria while the desk is unattended)
• Multiple simultaneous destinations (the door panel rings both the desk phone and the smartphone simultaneously)

This SIP architecture means the IP intercom is not a separate system — it is an extension of your existing IP PBX infrastructure. Management, call routing, and call recording all use the same infrastructure as your internal telephone system.

Door Release via SIP

When the indoor station user decides to admit a visitor, they press a configured key on their IP phone to send the door release command. The IP PBX relays this command to the door station, which activates its relay output and releases the door lock. The sequence is: visitor presses button → SIP call to reception → receptionist sees visitor on phone screen → receptionist presses door release key → door opens.

The entire interaction is logged in the IP PBX call records (who answered, at what time, how long the call lasted, who triggered the door release) and optionally in the access control system's event log (if the access control system also monitors the door state).

Door Panel: Mounting Options and Construction

Door stations come in three main mounting configurations:

Flush Mount (Recessed)

Flush-mounted door stations are installed into a cutout in the door frame, gate post, or wall surface. The panel face sits flush with the surrounding surface — a clean, professional appearance. Flush mounting requires a back-box depth of 50–80mm behind the mounting surface, which must be accommodated in the door frame or wall construction.

For new construction in Bangladesh commercial buildings, specifying flush-mount intercom back-boxes during the construction phase is far easier than retrofitting them later. For renovation projects, flush mounting is possible but requires careful joinery or masonry work around the back-box.

Surface Mount

Surface-mounted door stations attach to the front face of the wall, door frame, or gate post via screws. The panel body protrudes 30–60mm from the surface. Surface mounting is easier to install, particularly in retrofit situations, but the protruding body is more vulnerable to physical damage and weather exposure.

Stainless Steel Heavy-Duty Panels

For high-traffic public entrances, car park barriers, and security perimeters, heavy-duty stainless steel door stations provide mechanical durability (resistant to vandalism, impacts, and weather) with IK10 vandal resistance ratings and IP65 or IP67 weatherproofing. These panels are used for main building entrance doors, parking barrier control points, and any outdoor location exposed to weather.

Leading brands for stainless steel IP door stations include Fanvil i-series panels (i16, i32V, i62V) and Hikvision DS-KV series.

Integration with Access Control: Seamless Entry Management

The most valuable integration for a commercial building is between the IP intercom system and the access control system. Without integration, these are two separate workflows: visitors who have been admitted via intercom must still present an access card to pass through the access control-controlled door — requiring them to be added to the access control database before they can enter. This is impractical for visitor management.

Direct Relay Integration

The simplest integration: the door station's relay output is wired directly to the door lock (magnetic lock or electric strike). When the receptionist triggers door release via the intercom SIP call, the relay opens the door lock directly. No access control system involvement. This is suitable for main visitor entrances where access decisions are made by receptionists rather than by automated access rules.

Access Control System Integration

In a more sophisticated deployment, the IP intercom and the access control system (ZKTeco, HID, or equivalent) are integrated via API or through the access control system's door controller. The intercom call informs the access control system that a visitor is requesting entry. The access control operator grants access through the access control management software, which releases the door lock through its own controller. This approach provides a unified audit trail — visitor entry events logged in the access control system alongside card-reader events — which simplifies security reporting and incident investigation.

Multi-Tenant Apartment Intercom Systems

IP intercom technology has transformed apartment building visitor management in Bangladesh's rapidly growing residential high-rise sector. A traditional apartment intercom system uses dedicated two-wire cables running from a ground-floor panel board to each individual apartment's indoor station — a massive wiring installation in a 20-story residential tower.

An IP-based multi-tenant intercom system replaces this dedicated wiring with the building's existing data network infrastructure. Each apartment's indoor station connects to a nearby data outlet (the building's structured cabling system), and the door panel at the ground floor lobby connects to the network and communicates via SIP to each apartment's registered extension.

The visitor experience: the visitor arrives at the lobby panel, searches for or dials the apartment number. The system calls the resident's indoor station (and optionally their smartphone app simultaneously). The resident sees the visitor's image, speaks to them, and presses the door release button — all from their apartment or from anywhere in the world with an internet connection.

For Bangladesh's new residential towers in Bashundhara, Uttara, Dhanmondi, and other high-density residential areas, this IP-based multi-tenant intercom approach is increasingly the specified solution. It scales to any number of apartments with minimal additional infrastructure and eliminates the dedicated wiring cost that makes traditional multi-tenant systems expensive in tall buildings.

Bangladesh Residential Complex and Office Building Context

Commercial Office Buildings

In Dhaka's Grade A office buildings, visitor management is a daily operational challenge. Corporate tenants expect smooth visitor processing — visitors who have been pre-registered in the building management system should be admitted quickly, with appropriate identity verification and audit trail. IP video intercoms integrated with access control provide this capability.

A typical Dhaka Grade A office building deployment:

• Main lobby: 2–3 surface-mounted HD IP door stations with keypad for intercom extension dialling
• Each floor lobby (if floor access is controlled): flush-mounted door station at the floor entrance, calling the tenant reception
• Parking entrance: heavy-duty IP intercom at car park barrier, integrated with barrier gate control
• Service entrance: separate IP door station calling security control room

Brands SSAL Recommends

Fanvil: Fanvil's i-series IP video intercoms (i16, i32V, i62V) are purpose-designed SIP door stations with excellent call quality, robust construction, and full compatibility with all major IP PBX platforms. The i62V with 2MP wide-angle camera and flush-mount installation is our recommendation for corporate office lobby entrances.

Hikvision: The DS-KV series IP video intercoms from Hikvision integrate seamlessly with Hikvision's access control (DS-K series) and CCTV platforms, providing a unified security ecosystem with a single management interface.

Dahua: Dahua's VTO series video intercom panels offer competitive pricing with solid build quality and integration with Dahua's access control and CCTV systems. Suitable for mid-tier residential and commercial deployments.

Planning Your IP Intercom Deployment

A successful IP intercom deployment requires coordination between the network infrastructure, access control, and IP PBX teams. Key planning decisions:

• How many door stations and where?
• Which indoor stations (IP phones, tablets, dedicated indoor monitors, smartphone apps)?
• SIP registration: on the building IP PBX or standalone SIP server?
• Door lock type: magnetic lock (fail-safe), electric strike (fail-secure), or motorised bolt?
• Access control integration method: direct relay or API?
• Visitor management: does the receptionist visually identify visitors, or is there a visitor pre-registration process?
• Video recording: should intercom calls be recorded for security evidence purposes?

Get Free Consultation — Contact SSAL to discuss IP video intercom and door entry system design for your commercial building or residential complex. We design, supply, and install systems that integrate seamlessly with your existing IP PBX and access control infrastructure.