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Intercom entry systems are an important component of an effective property security system. Their use allows for two-way audio or video communication between occupants and visitors so that occupants can verify a visitor’s identity before granting full property access. 

Intercom security systems are flexible. Depending on your needs, they can be deployed as a stand-alone physical security solution or operate as part of a wider access control network supported by additional visitor and delivery management systems. 

Modern intercom systems are widely used in many different types of buildings, including residential homes, multi-tenant apartment complexes, condos and gated communities. Similar systems can also be found in commercial office blocks and campuses, industrial sites, educational establishments and public buildings. 

Although the scale and complexity of these systems can vary by use case, many basic intercom components remain the same. Common installations range from simple intercom doorbells to touchless intercom systems — as well as smart intercom systems that can be integrated with smart building technology and management solutions. 

To help readers choose the most appropriate door intercom system for their properties, this guide outlines the operation and key components of modern security intercoms, alongside a range of common applications and expected benefits for occupants and building owners alike. 

What is an intercom entry system?

An intercom entry system is a security solution designed to control access to a building by providing occupants and property owners a way to visually verify all access requests made by visitors such as couriers, contactors and maintenance staff.

The job of an intercom access control system is to provide convenient access for visitors while maximizing security. Unlike other forms of access control, which require authorized users to present valid credentials to an installed reader, intercom security relies on two-way communication. This communication takes place between a visitor and the person they are visiting, or a third-party, such as a concierge, the building employees or a security officer. 

There are two ways for visitors to identify themselves. They either speak to their contact using intercom speakers stationed at the main door of the property, or show their face to a video camera integrated within the door entry panel. These systems are known as door entry intercom systems, or simply entry intercom systems.

Intercom technology relies on the occupant recognizing the visitor. If they do, they can use a remote door release system inside the property to allow them to enter. While this can be a simple and effective form of security, it does pose a risk if intruders make false claims about their identity. Resident risk and the chance of a security breach are why it’s important that other forms of security, such as CCTV cameras, are in place.

IP intercom door entry system requirements 

Modern intercom systems offer a simple, efficient and secure method for handling visitor access requests. To operate these systems effectively, a few important requirements must be considered:

Ensure visitor access is convenient – When visitors arrive, an effective intercom door entry system should make contacting the front desk or the individual they wish to visit easy, simple and secure. 

Give occupants information on visitors’ identity – Occupants not only need to know when a visitor has arrived, but also the details of the visitor’s identity. To allow occupants to easily validate visitors, an intercom security system should enable visitors to communicate their identity – either by voice or via visual communications. 

Visitor management — Security teams will need to keep up-to-date records of all present individuals within a visitor management system for use in the event of an emergency. Intercom systems should be designed to accommodate this using reliable recordkeeping software.

Produce high-quality data – To enable the occupant to accurately verify the identity of the visitor, the intercom security system should provide accurate audio or visual information. For this, the intercom speaker must provide clear audio and the video camera must communicate high-resolution images.

Simplify access for delivery workers – An intercom entry system should provide fast, simple access for couriers delivering mail, food or packages. The system should also enable a streamlined process for companies providing regular delivery services. 

Reduce administrative burdens – A door intercom system should reduce the burden of visitor accreditation on front desk or security staff by enabling occupants to manage their own visitor access requests.

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Types of door entry intercom systems 

Generally speaking, modern intercom entry systems can be divided into six basic types, with each style well-suited for use in certain installations. These include:

  • Intercom doorbell – The visitor alerts the occupant by selecting a name from a directory on a door panel and pressing an intercom with a doorbell buzzer.

  • Intercom speaker system – The visitor selects a name from the directory and the occupant and visitor speak to each other using a microphone and speaker on the door panel. 

  • Intercom with phone system – The visitor selects a name from the directory, which then rings the occupant’s landline phone. The visitor can speak with the occupant using the microphone and speaker on the door panel. 

  • Intercom with cellphone system – The visitor selects a name from the directory, which then rings the occupant’s cellphone. The visitor can speak with the occupant using the microphone and speaker on the door panel

  • Video intercom system – A video camera fitted to the door panel allows the occupant to see the visitor. Both parties can also speak if a speaker and microphone system is present.

  • Touchless intercom system – Instead of pressing an intercom buzzer, the visitor waves their hand in front of a motion sensor fitted to the door panel, alerting the front desk. 

Intercom systems also can also be separated by their wiring configurations. Though 2‑wire intercom systems are the simplest and cheapest style, they are only designed to send and receive audio – with no control over who talks and who listens at any given time. Choosing to install a 3‑wire intercom system or a 4‑wire unit adds this control via a connection to an intercom matrix.

A wireless intercom system is another option. These systems use telephone lines of mobile phone connectivity to open a line of communication between speakers. Using Wi-Fi signals provides a remote communication option for the occupant.

Security levels for intercom entry systems 

Different types of intercom systems offer different levels of security. Intercom speaker systems, intercom phone or cellphone systems and intercoms with no additional IP security camera system integrations offer the lowest level of security, as the occupant must rely only on audio information to verify the visitor’s identity. On the other hand, touchless intercom systems offer a high level of convenience to the visitor, but, like other basic systems, they typically only provide voice-based communications. 

Video intercom systems are typically the most secure option as the occupant is able to visually verify each visitor’s identity as well as request additional forms of verification to the camera such as ID badges.

Door intercom system components

Most intercom entry systems have the same basic components:

  • Base stations at the entry point 

  • Substations for each occupant to receive access requests 

  • Directories of users in a building with intercom connections 

  • Connectivity systems to link base stations to individual substations 

  • Electronic door locks and security doors 

  • A power supply for the base stations and door locks 

  • Infrastructure for intercom security system management

Base stations

Base stations serve as the first point of contact for visitors. They are installed at each entrance used by visitors – front doors, main entrances, car park entrances or barriers and entrances to gated communities or industrial sites. 

Base stations house the hardware for intercom door entry systems, which includes an intercom buzzer, a directory of occupants, a microphone and an intercom speaker. In video intercom systems, base stations also incorporate a high-definition video camera. 

Base stations for outdoor intercom systems are housed in door panels mounted on or at the side of doors, entrances or gates. For security purposes, base stations must provide reliable operation under all weather conditions and should be tamper-proof to deter vandals or criminals. 


Substations receive and respond to access requests. In commercial properties, these devices will typically be located at the front desk, main reception and/​or inside the business’ primary security office.

In a multi-unit apartment building security system, each unit would have its own substation, so that visitors can contact individual residents directly. Traditionally these substations will have dedicated devices installed within each unit, though modern intercoms can be configured to use existing laptops, computers and smart devices as a suitable substation display.

Increasingly, mobile devices such as smartphones or smart watches are using an intercom app as substations. The apps provide the functionality to handle audio or video intercom requests as well as remote door release, allowing users to remotely provide visitors with access even if they are not close to a fixed substation. These mobile devices can also be used in many different applications. In commercial office buildings, for example, mobile devices offer a more practical, inexpensive solution as opposed to dedicated intercom displays for each employee


Base stations for intercom security systems contain dedicated directories with the names or unit numbers of all users within a building. These directories can be stored in a local service or cloud. Visitors can search the directory to find their contact, then press an intercom buzzer with door release button to initiate contact. It is important that security staff or property managers keep the directory up to date by adding or removing names when changes occur. 


Three main types of intercom connectivity link base stations to individual substations – hard-wired intercom systems, local or wide-area networks (LANs or WANs) and wireless intercom systems. Connectivity solutions support a number of intercom door entry system functions – they transmit alerts when visitors press an intercom buzzer, communicate two-way audio or video messages between base station and substation and send door release system signals from substations to electronic door locks. 


Cost is an important factor when comparing connectivity solutions. Networks are a more cost-effective solution than 2‑way wired intercom systems, which can be expensive to install or replace if there are large numbers of individual users. Because a single LAN, WAN or wireless intercom network can be installed throughout a building, each substation only requires a local connection. Furthermore, adding new substations requires a local connection to the network rather than new cabling. 

The network must have the capacity, bandwidth and performance to transmit intercom security and door release system signals at high speeds, even under heavy traffic conditions when visitor numbers are high. 

  • IP intercom systems – Modern intercom systems use IP (Internet Protocol) technology to transmit signals in buildings where there may be hundreds of individual base stations. By using a predetermined set of rules or protocols, these IP internet intercom systems also called intercom over IP systems organize data into packages’ suitable for transmission on IP networks. These rules enable data to be exchanged between intercom devices that have individual IP addresses. In a typical intercom door release system, the connected devices include base stations, substations, management systems and electronic door release systems. To give critical two-way intercom communications priority over other network services, the best networks for IP-based intercom systems incorporate features such as automatic rerouting to avoid network congestion and traffic prioritization. 

  • Wireless intercom systems 2‑way wireless intercom systems offer a flexible solution for occupants who need to receive access requests on mobile devices in any part of a large building. For example, a wireless doorbell intercom system can be useful if a building has numerous communal areas such as lobbies, refreshment areas or gyms. Intercom wireless networks must be carefully planned and installed to ensure reliable signal strength throughout a building. If any areas experience weak signals, intercom services may fail and become frustrating for residents.

Electronic door locks 

Intercom with door release systems allow occupants to open doors or gates remotely by sending door release signals from a substation inside the property or a mobile app. The door release system signal triggers a relay which in turn releases an electronic door lock, of which there are two types: an electric strike lock or a magnetic strike lock. 

Electric strike locks replace the conventional lock strike plates found in most security doors. In this type of lock, an electric motor holds the strike plate in the locked position when a current is flowing. When an occupant sends a door release signal, the relay on the base station enables the motor to release the strike plate so that visitors can open the door.

On the other hand, magnetic strikes incorporate an electromagnet on the door frame and a metal plate on the door. When a current is flowing, the electromagnet and door plate bond to lock the door. A door release signal cuts the flow of power, thus breaking the magnetic bond and allowing the visitor to open the door. 

Power supply

Each component of the door release intercom system – including all base stations, fixed substations and electronic door locks – will require a continuous power supply to function. Hard-wired intercom systems require dedicated cabling, while IP-based intercom systems can utilize Power-over-Ethernet (PoE) technology drawn from a connected network. A PoE supply can often reduce the overall cost of an installation by eliminating the need for dedicated cabling, whilst also making it easier to add additional intercom devices at a later date.

Infrastructure for intercom entry systems

The infrastructure for a door intercom system can either make use of physical on-site servers or be hosted in the cloud. There are pros and cons to both options. Physical servers will be managed and maintained by on-site IT and security teams, requiring any updates to be applied manually by in-person teams. If the intercom entry system is to be expanded, server capacity will also need to be added on-site.

Alternatively, many modern intercom systems are cloud-based, meaning all management, maintenance and update functions are applied automatically by the cloud service provider. Unlike those with physical on-site servers, cloud-based intercom system expands, security and IT teams can simply request that the capacity be expanded on-demand. 

For these reasons, cloud-based infrastructure often offers much greater flexibility and convenience to the user – though only if the connection remains strong. Furthermore, occupants or security teams can access intercom system data from any Internet-connected fixed or mobile device in any location. With these remote controls, occupants can handle access requests or open doors, while security teams or property managers can review intercom data, update directories or manage the system without having to be on-site. 

Use cases for intercom door entry systems 

Commercial office buildings

Visitors to an office complex may wish to contact a specific individual inside the building, be that a department within a company or a particular reception desk. An intercom with phone system gives visitors and occupants the flexibility to establish contact with multiple residents within the complex from a single, easily-navigated platform. 2‑way wireless intercom systems for commercial security systems are a cost-effective solution for larger office complexes, allowing occupants to use multiple mobile devices as sub-stations, rather than investing in large numbers of dedicated displays. 

Residential buildings

Convenience is of utmost importance to residents. Intercom door entry systems give tenants in multi-unit apartment complexes and residents of condos and gated communities a simple and convenient way to deal directly with access requests from friends, family or visitors like delivery staff. The added convenience and security provided by front door intercom systems can also help to increase resident satisfaction levels and add value to the property. 


Intercom systems can be used beyond residential settings. In school security systems, intercom systems stationed at perimeter gates and main entrances form an essential first line of security and protection against intruders. These systems should be linked to the school’s front desk and incorporate some form of school security camera system so that school security staff can request multiple forms of identification from visitors before being granted access to the property. 

Industrial sites

Outdoor intercom systems provide a useful first point of contact for visitors or delivery drivers entering industrial sites with multiple secured entrances. These systems allow guests to contact a central security office to request access or a centralized front desk. They can also be integrated alongside additional security systems such as business video surveillance cameras and motion sensors to alert security staff to the presence of unauthorized intruders during working and non-working hours.

Intercom entry system benefits

Intercom systems provide several important benefits for building occupants, visitors, security teams and property managers alike, with some of the most prominent being: 

Stronger security – Visitors can only enter a building when they have received authorization from an occupant or from a front desk. Data from the intercom system can also provide security professionals with a more transparent view of suspected incidents to help teams better understand potential threats and improve their operations. 

Visitor convenience – Intercom door entry systems provide a simple, convenient way for visitors to gain access to a building. Door intercoms offer various methods for visitors to establish their identity and, with a wireless intercom with door release function, guests no longer need to wait for physical assistance to enter the property. 

Simple delivery management – Modern intercom systems make it much easier for building owners and residents of multi-tenant residential properties to sign for and accept incoming deliveries from couriers and delivery drivers. Additionally, this intercom system can be linked to a central delivery drop-off and collection point, allowing couriers to contact occupants directly. Door intercom systems can also incorporate facilities for authorizing credentials used by couriers who deliver regularly to the same building, such as providing staff with one-time access codes or an ID badge system where drivers are asked to present credentials to a fixed camera. 

Reduced administrative burden – With an intercom access control system linked to each occupant’s personal substation, reception staff will no longer need to grant access to every guest, and security teams will be free to focus more on wider aspects of their roles.

Increased property value – By increasing both security and convenience for the user, installing door entry intercom facilities throughout a building may increase the value of the property and make it easier to attract and retain occupants.

Planning an entry door intercom system 

Modern intercom entry systems can be installed in buildings as an additional form of security or deployed as part of a project to upgrade or replace existing forms of access control. To ensure that all systems are working correctly and free from exploitable security flaws, it is important that intercom installation and intercom replacement be performed by a professional security installer.

In buildings with large numbers of occupants, intercom systems must have the capacity to secure multiple entrances and substations in all units. They should also have the flexibility and scalability to allow for additions or changes to be made if the building is later modified. 

Choosing a reliable network for your security system is vital in minimizing delays and ensuring a seamless visitor entry process. The network chosen to support two-way communications for intercom with door release systems must have the speed, performance, bandwidth and reliability to transmit access requests and door release instructions quickly.

Occupants should not experience difficulty in handling access requests even at peak times. If a wireless front door intercom is being proposed, property owners must also consider the capabilities of the wireless network they intend to use, as the wireless network must be able to provide consistent signal strength throughout the property. Furthermore, intercom entry systems should incorporate components that are reliable and require minimal maintenance. Outdoor intercom systems should be weatherproof and tamperproof so they have the ability to ensure reliable operation in all conditions. 

To reduce connectivity costs, property owners should consider minimizing the use of dedicated cabling by instead using existing networks to connect base stations and substations, as well as using PoE technology from the network to supply power to individual intercom components. 

Where possible, intercom components should be designed and built to open standards, so that they can be integrated with a wide range of compatible security systems, such as pan tilt zoom cameras and intruder detection sensors as well as property management systems, including fire alarms, smoke detectors and environmental control systems. Integration at this high level can act to increase security and safety throughout the property. 

Choosing a door intercom system for your property 

Choosing to install and operate a modern intercom security system can present a range of important benefits to both property owners and residents, with a large variety of styles available at multiple price points. However – with a range of intercom companies and intercom manufacturers to choose from, each specializing in systems designed to suit particular use cases and needs – it’s often best to seek professional advice before investing in a door intercom system for your business. 

To help plan and implement an ideal solution, security system professionals can provide much-needed support and guidance, whether that’s working to replace old intercom systems, convert legacy intercom systems or designing and implementing entirely new intercom systems. Security system installers can also provide practical support in the form of advice and detailed specifications, site surveys and intercom system installation services customized to the needs of the property.

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