Comprehensive intercom system technology guide

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What is an intercom system?

At its simplest, an intercom system is a set of devices that allow two-way communication between two points. Earlier intercoms, or ‘walkie-talkies’ as they were known, enabled people to talk to each other within a building or campus. 

The mobile phone has taken on that communication role, but modern intercom systems now have an important role to play in security. As part of an access control system, an intercom security system allows people within a building to hear or see the person who wants to enter before granting access by opening a door or gate.

Their primary role is to enable and manage communication and secure property access. That makes door intercom systems an important component in a commercial security system to protect people and property across different industries and applications. Intercom entry systems provide a cost-effective alternative to other forms of access control and they can also be used as part of a secure visitor or delivery management system.

Components of a door intercom system

Base stations

The base station or master station is installed at the entrance to a building or front door and is connected to one or more substations inside the building. Visitors use the base station to communicate with occupants via audio (voice control) or video to request access.

The base station requires a power source, wired or wireless connectivity to the substations, and a release mechanism to open the door or gate when the occupant authorizes access. In larger campus sites, there may be several base stations at different access points, all connected to a single substation. 


Substations are installed at various points throughout a building, depending on the structure of the system. In an office block or campus, for example, a receptionist or security officer might handle access requests. In an apartment block, each apartment might have its own substation. In a single home or standalone office, there would only be one substation. 

Substations can take various forms. Depending on the type of building, occupants might use a microphone, a computer screen, a surveillance monitor, or a smartphone to handle the request and respond to the visitor.  

Intercom buzzers 

Audio and telephone entry intercom systems incorporate a buzzer, microphone and speaker in the door device so that visitors can speak to occupants and hear their response. Visitors press the buzzer to alert the occupant and activate the microphone and speaker. 

Video cameras

Video-based intercom base stations also incorporate a built-in camera that captures and transmits an image of the visitor to the substation. Occupants may also use the audio function if they need additional information from the visitor. 


Smartphones are becoming the preferred alternative to substation hardware. They support all forms of intercom requests - audio, video and telephone-based - and they reduce costs because occupants don’t have to buy substation hardware or pay installation costs. Smartphones can use apps that allow occupants to open doors remotely using an internet intercom system or web-based intercom system. Smartphones also increase flexibility, because occupants can handle access requests from any location via the Internet. 


Base stations are connected to substations through either a wired or wireless connection. A wired connection requires cabling from the base station to each substation. A wireless solution requires a reliable wireless system with the coverage and reach to connect base stations and substations throughout a building.

Door locking and release system

The door or gate that is protected by an intercom entry system requires a lock and a release mechanism that occupants can operate remotely to grant access. The door can incorporate an electric or magnetic strike lock connected to the intercom device. In some simpler systems for businesses, the visitor presses an intercom buzzer to release the commercial door lock when the occupant has granted access. 

Power supply 

An intercom access control system requires a power source for the base station and its audio or video and door release components. Power can be supplied by a mains system or by connecting to a data network and using Power-over-Ethernet (PoE) technology. 


Depending on the type of intercom system, software can be incorporated in the substation or smartphone to support communication and door release. In more complex commercial systems rather than in a standard home intercom system, directory software can be used to streamline access for authorized visitors, route calls to the correct person, and provide audit trails. 

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The all-in-one touchless intercom security system from Openpath

  • Industry-leading unlock speeds with touchless entry

  • Built-in 5MP camera with live video and cloud storage 

  • AI-powered voice recognition and mobile video calling

  • Backward compatible to work with any access control system 

  • Convenient cloud-based management with 100% remote access

  • Real-time access alerts with video monitoring and two-way audio

  • Easy snap-in installation with a single PoE cable

Intercom technology options 


Audio is the simplest form of intercom communication. An audio intercom buzzer with door release button works by a visitor pressing a buzzer and speaking to the occupant, giving their name or the reason for their visit. In a commercial application, the intercom might be integrated with a visitor directory so that a receptionist or security officer can verify identity or ask for further credentials. 

Although audio-based systems are simple and reliable, they depend on trust. A visitor could use a false name to gain access with no further verification needed. This is why these doorbell intercom devices are primarily used for home security. This type of intercom doorbell smart home technology is ideal for family members at home, but businesses or commercial building owners may want to invest in something more secure than an audio-based intercom system with door release.


Another form of audio communication uses landline or mobile telephone systems to connect visitors to occupants. This is known as an intercom with phone system. Occupants provide a phone number which is displayed in a directory at the entrance. Directories can be written out, or digital depending on the type of base station hardware. Visitors select the number and initiate a call. When the occupant answers on their phone and recognizes the visitor, they key a number to release the door and grant access.More modern intercom systems can leverage mobile phone apps to handle calls and door release. 


A video intercom incorporates a high-definition camera to capture an image of the visitor. Door intercom devices can feature a built-in camera, or use an external camera, such as a surveillance camera. The intercom system sends the visitor’s image to a screen or smartphone. For commercial applications, a centralized video intercom substation is common, but smartphone video intercom systems allow users to monitor visitor activity from anywhere on their mobile device.

Depending on the type of camera, it may provide a direct view of the visitor from a fixed viewing angle. Other cameras can be adjusted by the occupant to get different viewing angles. A camera with a wider viewing angle can be useful for checking if there is more than one visitor. Intercom security systems with a video surveillance camera can also record time-stamped footage of every visitor, which can provide valuable audit information in the event of a security breach.

Video-enabled intercom technology is evolving quickly to add new layers of security, convenience and functionality. For example, smart intercom systems are available that allow hands-free voice activation for visitors, plus live video available to the occupant. In more advanced and secure solutions, the intercom system can be integrated with artificial intelligence technologies to support functionality such as call routing based on user preferences, entry schedules, and visitor responses.

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Types of intercom security systems 

There are a number of types of intercom security solutions, including wired or wireless intercoms, cloud-based intercom systems. They use different technologies to support communication. In audio systems, a visitor presses an intercom ‘buzzer’ on an external device and speaks to the person inside the building. This is a typical intercom with a doorbell. Security intercoms with video systems incorporate cameras so that the person inside the building can see the visitor. Telephone-based intercom systems use telephone landlines or mobile networks to allow visitors to contact occupants. The intercom system transmits the audio or video to the occupant’s device and that allows occupants to recognize visitors’ names or faces before deciding whether to grant access. 

There are different types of wireless intercoms that can be used to manage access for a wide variety of properties, from domestic residences and multi-occupant apartment blocks to offices and other commercial or industrial buildings.

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Intercom connectivity options

Intercom base stations can be connected to substations by a number of connectivity options, including: 

Wired intercom systems 

Wired systems require two types of cabling – cabling to provide power to the intercom components and cabling to connect the base station or stations at the entrance to the substations in the building. 

A property with a large number of substations will require professional installation of cabling throughout the building to support two-way communication for each occupant or user. This can add significant installation costs and increase deployment time. The system is also inflexible as new cabling would be required to connect additional users.

A hardwired intercom system using high-grade, low voltage Cat 5 or 6 cabling provides reliable connectivity requiring minimal maintenance. It should ensure a clear audio or video signal without the risk of signal degradation through interference. Communication is clear and the system provides a high level of security. 

Wireless intercom systems

A wireless intercom system, in comparison, does not require extensive cabling to connect small or large numbers of substations. Instead, it uses a Wi-Fi system to transmit signals throughout a building. 

The Wi-Fi system uses radio frequencies to transmit signals. The clarity of communication depends on the quality and strength of the signal, and the coverage and reach of the wireless system. For example, a wireless system may only have the bandwidth to carry audio signals, not video. Some buildings may have areas where wireless coverage is poor. 

That makes it important to check the quality and reach of a wireless intercom system throughout the building. Poor performance in certain areas may require the installation of boosters to strengthen the signal. Wireless systems can also be prone to interference from other electrical devices, so it’s important to select a high-quality, high-bandwidth system to overcome any potential issues. 

Despite the potential problems, wireless intercom security offers many important benefits. 

  • They require no extensive cabling to connect substations. 

  • They are simple to set up and installation costs are low.

  • They can connect all areas of a building, provided coverage is effective.

  • They can utilize smartphones as substations, eliminating the cost of physical substation hardware. 

  • They improve convenience and flexibility by allowing occupants to manage access remotely from any location via the Internet. 

Network-connected systems 

In larger commercial buildings and campuses, base stations can be connected to substations using an existing IP data network as the transport systems. This is known as an IP based intercom system. This provides wired connectivity without the need to install dedicated cabling for the intercom which also allows it to be easily connected to an IP door access control system. The IP intercom system can use the bandwidth and security of a corporate network to carry audio or video signals quickly, reliably, and securely (intercom over IP). 

Mains-wired systems

In residential intercom door applications, the mains electrical system can provide a low-cost alternative to dedicated wiring or wireless broadband. The intercom cabling can be connected to a plug-in device at the base station and any substations connected to broadband Internet. The signal is transmitted through the mains system. 

Telephone-based systems

This type of intercom requires a telephone cable connected to the base station for landline users, or a cellular connection for mobile users. While most commonly used in multi-family residential entry intercom systems, the prevalence of smartphones is allowing more enterprise businesses and commercial buildings to take advantage of mobile intercom technology.

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Intercom system installation

The cost and complexity of intercom installation is dependent on a number of factors:

Base stations are installed at entry points – doors or gates. Depending on the structure of the door or gate, installation can be simple or more complex if a device has to be fitted flush, for example. Where the base station is installed can also factor into the cost and type of intercom needed. It’s important to note that intercom entry system base stations need to be simple to find and use for visitors, so should be easily accessible, close to the doors they control, and have an intuitive intercom doorbell or buzzer design.

Substations can take different forms. They may use existing computer screens or smartphones, or require special monitoring devices that have to be installed and connected.

Cabling is required for wired systems to connect base stations and substations. This may require complex cabling runs through a building or it may use existing cabling such as data networks, telephone lines or mains systems. Cabling will also be required to provide power to the base station.

Location of substations can influence cost. Larger buildings using wired systems may require long cable runs to reach the furthest points. If the building is using a wireless system, additional boosters may be required to maintain signal quality. 

Weather protection is important for outdoor intercom security with base stations on external doors or gates. The hardware must be weatherproof to a standard such as IP65 so that the base station is protected against damage from rain or dust. 

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Intercom systems for different applications

Intercom security systems are used to manage access in a number of different applications, including: 

Home intercom systems 

Residents can use a front door wireless intercom or wireless doorbell intercom system to check the identity of visitors before opening a door. A 2-way wireless intercom system like this supports one-to-one communication. These devices are meant for a single door, without many of the security and usability features needed for a business or multi-family complex.

Intercom entry systems for multi-tenant residential buildings 

There is usually one main access point (such as a lobby) and each occupant can connect to the main door to communicate with visitors using the apartment intercom system. Some higher-security multi-tenant buildings may also have a nominated person who controls access on behalf of the residents. Some residential apartment and condo buildings also allow tenants to give visitors access to amenity spaces, parking garages, elevators, and unit doors. 

Commercial buildings 

There is generally a single main locked entrance to a commercial office building covered by a business intercom system. Visitors request access by contacting a central point, such as reception or a security desk, or they may contact individual employees directly. An intercom security system can also be configured to allow out of hours access to be controlled remotely or from a central point. 

Industrial buildings 

In buildings such as factories or warehouses, access may be controlled by an intercom security system during working hours or when the facility is closed. Access for industrial buildings is likely to be managed by a security control room that monitors deliveries, visitors, and personnel.

Parking lots and garages 

Car parks with restricted access have gates with outside intercom systems that enable visitors or authorized employees or residents to request entry. A touchless intercom system would be best suited for a car park. 

Gated entrances 

Gate entry systems can be used to manage access to gated communities, industrial properties or larger areas where access is restricted. Gate intercom systems include a buzzer so that visitors can contact a security officer or a community resident to request access. Rather than requiring visitors to search through complicated directories, some modern intercom systems offer touchless, voice-activated call routing with keyless door entry.

Visitor management integration 

Commercial buildings with large numbers of visitors can use an intercom unit or intercom door entry system integrated with a visitor management system, which can streamline access for authorized visitors. For example, occupants can provide authorization codes for visitors to use over the intercom. If the intercom access control system has built-in reader functionality, pre-authorized visitors could also scan a guest pass QR code to gain entry. This increases security and convenience. 

Delivery management integration

The growth of online purchasing has increased the number of deliveries to both residential and commercial buildings. Integrating intercom access control systems with delivery management systems can also streamline deliveries. Similar to visitor management systems, occupants can provide delivery staff with access codes. With a mobile-based intercom system, delivery personnel can call the recipient directly to get delivery instructions, even if the person is not at the building.


In campuses with many buildings and many access points to manage and secure, individual intercom systems can be configured as part of an exchange intercom system. Individual base stations are connected to an exchange or central controller, which routes access requests to the appropriate substation. This approach ensures consistent standards of access control across the campus and reduces management complexity. 

Integration with security programs

As well as providing standalone solutions for managing door entry, intercom systems can be integrated with your security technology by integrating them with security management or surveillance systems.

For example, in a commercial building, video-based door intercoms can connect visitors directly with employees, but the system can be configured to also provide security teams with a view of the door. Security teams can then identify issues such as attempts at forced entry or doors left open to allow tailgating. Door intercom security can also be integrated with audit systems so that security teams can review the performance of intercom systems and monitor any unusual patterns that might pose a security risk.

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Selecting an intercom system

Security intercoms are suitable for a wide variety of access control applications. When selecting a system, it’s important to take a number of factors into consideration, including:

Security is the most important feature. The intercom system provides some fantastic security features, and must allow occupants to identify visitors before granting access. That makes video-based intercom systems a better choice, because occupants and security teams can recognize visitors more easily.

Convenience for occupants and visitors is essential. The door or doorbell intercom should be easy to use for both parties. The increasing use of smartphones as substations has improved convenience because users can handle access requests and open doors from any location without having to find and use special equipment. 

Flexibility is important where a building has a large number of users and is subject to change. A fixed wired system cannot be easily adapted to add new users or change existing ones. With a wireless or networked system, the intercom system is easily scalable to accommodate growth or change. 

Reliability is essential to maintain security and protect occupants and property. An outdoor intercom system must be protected against weather damage, and the connectivity must be reliable. Wired systems should use appropriate cabling, and wireless systems must be capable of reaching all users in a building with strong clear signals for both audio and video. In addition, the locking mechanisms of the intercom entry system needs to be reliable so that access control security is maintained at all times. 

Cost and intercom pricing is a factor that must be considered from a long-term perspective. In addition to the up-front costs of hardware, it’s important to include installation, connectivity and maintenance costs to get a true picture of through-life costs. Some intercom system companies charge a flat rate no matter how many users are in the directory, while other providers may offer a more scalable tiered intercom pricing option. 

Would you like to upgrade your intercom system? 

Intercom systems provide a versatile, effective solution for a wide variety of access control applications. Although the basic concept of an intercom system is simple – to allow communication between visitor and occupant – advances in technology are increasing the security, convenience and functionality of these systems.

Intercom systems provide an important standalone solution to door access security. However, they can also be used in conjunction with access control systems as part of a comprehensive security strategy.

If you would like to convert or replace an old intercom system, Openpath’s Video Intercom Reader Pro features an easy-to-use mobile app, standard wiring for easy installation, and combines all your front door security needs in one device. Plus, the open standards means it works seamlessly with existing access control systems. To find out more about the Openpath smart intercom system and how it could benefit you, get in touch today.

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What is the best intercom system?

Choosing the right intercom door entry system is an important decision for any business. Take a look at the top intercom companies and intercom products currently on the market to compare which intercom security system is the right fit for your needs. 

Openpath Video Intercom

Openpath’s Video Intercom Reader Pro combines touchless access control, high-definition video, two-way calling, and an intercom doorbell in a single device. The smart intercom system has AI-powered voice for enterprise-grade call routing suitable for commercial offices and multi-family residential applications. Intuitive cloud-based software and mobile-optimized interface for fully remote management, enhanced mobile video monitoring, and improved visitor experiences. 

Key features 

  • Mobile video calling and remote unlock capabilities

  • Single-touch intercom doorbell and voice-activated call routing

  • Two-way audio with echo and noise cancellation

  • ONVIF Profile S and T compliant video platform

  • 5MP high-definition camera that supports WDR 

  • Backward compatible with any access control system

  • Touchless entry with mobile app, tablet app, Smart Watch, and key card support

  • Sleek hardware with single PoE cable

  • Easy snap-in installation with adjustable angle

  • IP65 rated for outdoor use

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ButterflyMX supplies a range of security-related products. Their intercom product is a video-based system that is designed to work with smartphones. The video intercom device can be used for door or gate access control in residential, commercial, and industrial applications and is designed to simplify visitor access and management. Other products include elevator controls, self-guided tours, and front desk stations. 

Key features 

  • Smartphone app for viewing requests and opening doors to support remote management

  • Wired or wireless Internet connection

  • Video calling for greater security

  • Directory of occupants simplifies searching for visitors 

  • Send visitors ‘virtual keys’ with QR code and delivery PINs

  • Access PIN allows owners entry if they forget keys

  • Can be integrated with property management and access control systems 

  • Door release logs with time and date-stamped photos

  • Range of surface and recessed models 

  • IP65 rated 

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Swiftlane offers a range of access control products, including video-based intercoms, facial recognition access, mobile unlock, PIN access and key card access together with a cloud–based dashboard that integrates mobile unlock, face recognition, video intercom, and visitor management systems.

Key features 

  • Video intercom offers face access and wireless video calling 

  • Video intercom features mobile app and remote door unlock

  • Video intercom offers delivery access and temporary visitor access

  • Face recognition door system allows visitors to look at the SwiftReader and the door unlocks

  • Face recognition system prevents unauthorized access via 2D and 3D depth data

  • Face recognition system SOC II and HIPAA compliant

  • PIN access system provides secure PINs for temporary visitor and delivery access

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AIPHONE Intercom System

AIPHONE provides a range of video intercoms and related components for different applications. The AIPHONE intercom products are available in different sizes with features specific to applications such as multi-tenant apartments, commercial buildings, and legacy systems. 

Key features

  • Cloud-based app (fees may apply)

  • All stations are powered by PoE

  • Touchscreen entrance panel

  • Updates can be programmed remotely

  • Built-in HID® reader

  • Scalable systems to simplify changes or additions 

  • Wired or wireless connectivity 

  • Smartphone apps for mobile and remote unlocking

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Latch Intercom System

Latch, as the name suggests, offers intercom and access control systems with door opening by latches integrated with their own operating system. The Latch intercom system offers centralized device management for property managers and smartphone control for users.

Key features

  • Intuitive user interface with tactile buttons

  • Receive audio calls at any phone number

  • Receive video and audio calls in the Latch App 

  • Remote unlock

  • Flexible connectivity options by Ethernet, Wi-Fi, and cellular

  • Accessibility features

  • Integrates with other access control systems

  • Microphone features automatic sensitivity adjustment, dual microphone, echo cancellation, and noise reduction

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ALPHATOUCH Video Intercom

ALPHATOUCH offers Cloud/PoE mobile- and monitor-ready video intercom platforms to support direct telephone dialing, mobile-app calling, and calling to one or more monitors or smartphones. 

Key features

  • Touchscreen or video entry panels in different sizes 

  • Occupant and visitor access can be scheduled to maximize security

  • Programmable occupant and visitor QR codes can be used to grant access

  • Cloud-based system with remote web management 

  • Integrates with existing analog systems

  • Maintenance alerts of any urgent maintenance requirements

  • All system activity logged with names and photos

  • IP65-rated for protection 

  • Surface and flush wall mounting options

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Hikvision Video Intercom

The Hikvision video intercom line offers a comprehensive range of products to enable convenient two-way audio and video verification for entry control. The range includes IP-based intercom system products, analog-based products, or 2-wire and 4-wire products to suit different applications.

Key features

  • Mobile app for remote opening and communication 

  • Choice of connectivity options 

  • Integration with CCTV systems 

  • 2MPx HD camera

  • One-touch calling 

  • IP65 water resistant

  • Choice of modular door and indoor stations

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Axis Video Intercom

Axis network intercoms combine video surveillance, two-way communication and remote entry control in a single device suitable for entrances and exits in individual buildings or campuses. Axis network intercoms offer secure, barrier-free entry and include accessibility features for hearing impaired individuals. Models with an integrated access control reader (RFID) allow secure, hassle-free physical access to premises for employees and known visitors.

Key features 

  • Use mobile app, IP phone, or video management system to open doors directly or remotely

  • Connectivity over IP network

  • Integration with other applications 

  • Audio and video analytics trigger audio alerts or recordings when visitors approach

  • HD video 

  • Audio with echo and noise cancellation

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Doorking Video Intercom

Doorking intercom systems is well-known for their on-premises intercom and access control systems. Also commonly known as DKS, Doorking offers telephone entry systems, keypad readers, card readers, and a video intercom system for both residential and commercial applications. With the recent addition of DKS Cloud and a mobile app, some Doorking systems can be managed remotely from a web browser or smartphone.

Key features 

  • Tactile button and keypad intercom entry systems

  • Connectivity via VoIP, cellular, or telephone service lines

  • Separate mobile apps for system management, user unlocks, and digital locks 

  • Call waiting and call forwarding available in some models

  • Video available as an add-on for some models

  • Outdoor rated

  • Tamper resistant

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