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Intercom systems allow two-way communication between separate areas. They have a variety of uses, from providing basic interconnectivity in homes and businesses to acting as a professional access control system for security purposes.

This comprehensive guide will discuss the various components of intercom systems, different types of applications and how to choose the right intercom security system.

What is an intercom system?

An intercom system is a device that allows communication between one or more people in different locations. The most basic type of intercom system is an audio-only device that can be used for simple conversations, such as announcing visitors at the front door. More advanced systems feature video and audio capabilities, allowing users to see and hear each other. Intercom systems are commonly found in businesses, schools and homes.

Modern intercom systems play an essential role in security. They can be used as a backup method of communication when phone networks are down due to a natural disaster or technical issue, making them essential for organizations with important security protocols that cannot afford interruptions.

Intercom systems also provide access control functionality, allowing authorized personnel to open doors remotely instead of having to physically go and open them every time there is a visitor. This makes commercial and office intercom systems invaluable for businesses that need to keep out intruders, along with providing secure access for employees at any time of day or night.

Intercom security systems can also be integrated with surveillance cameras so that security personnel can monitor activities taking place outside of their premises from anywhere in the world. Incorporating security intercoms with commercial surveillance cameras gives organizations an extra layer of protection.

How does a door entry intercom system work?

An intercom door entry system is used to control access at one or multiple entry points and involves a number of components:

  • Master station: This is the device located at the entry point and is used to communicate with visitors. It can take various forms, such as an audio speaker with a microphone, a video phone, or even a simple keypad. It connects to a substation either wirelessly or through a wired connection. The master station may also include a release mechanism, such as an electronic door opener, to allow access to the facility when authorized.
  • Substation: The substation is the device located in individual rooms or apartments. This can be a microphone, computer screen, surveillance monitor, or smartphone that allows occupants to communicate with and grant access to visitors. It connects directly to the master station for communication, allowing occupants to hear and respond to visitors.
  • Buzzer: Door entry intercom systems typically include a buzzer. When visitors press the buzzer at the master station, it alerts occupants in their office or apartment that someone is at the door and activates the microphone and speakers. This allows occupants to communicate with visitors before granting access.
  • Video camera: Some entry intercoms incorporate a built-in camera that captures and transmits an image of the visitor to the substation, allowing occupants to better assess a visitor and verify their identity before granting access. This feature is especially useful for apartment intercom systems used for multifamily residencies.
  • Access control: Some intercom door entry systems include access control mechanisms like electronic door openers. When an occupant grants access through the substation, the door opener unlocks the door, allowing visitors to enter. Intercom systems with door release can also be used to restrict access to certain areas and times of the day.
  • Smartphone apps: The popularity of smartphones has led to the development of mobile apps that allow occupants to control their intercom entry systems from their phones. Mobile access control allows managers to grant access to visitors from anywhere, greatly increasing the convenience of door entry intercom systems.
  • Connectivity: Intercom access control systems are typically connected to the substation through a wired or wireless connection. A wireless connection is preferable for most applications because it eliminates the need to run wires through walls and ceilings. Wireless doorbell intercom system connections are also more secure, as they are not susceptible to physical tampering. 
  • Power unit: Door entry intercom systems usually require a power unit to provide electricity for the master station and substation. Depending on the model, this may be an external AC power adaptor or an internal DC power supply. However, some wireless models have a built-in battery that eliminates the need for an external power unit. Though the battery life of these devices will vary depending on the model and the level of usage, they can typically last months between charges.
  • SoftwareIn more complex entry intercom systems, directory software can be used to streamline access for authorized visitors. For example, when a visitor presses the buzzer at the master station, the directory software can route calls to the correct person or department and provide an audit trail that details who granted access at what time. This allows for greater control and accountability when managing access to a facility.

Types of door intercom systems by function

Intercom door systems can be classified based on their function, type of technology and connectivity options. In terms of function, intercom door entry systems can be divided into three primary categories:

  • Internal communication: In this type of system, the intercom is used to communicate between rooms or apartments in a building. This can be helpful in situations where occupants need to communicate quickly with each other without having to leave their rooms. However, this type of intercom has largely been replaced by more modern communication options, such as mobile phones.
  • External communication: In this system, the intercom is used for communication between the substation and an external visitor. This allows occupants to communicate with visitors. However, since it is not a door release intercom system, occupants must still physically open the door to allow access. This type of intercom is often used in small residential applications, such as single-family residences, where a door release system is unnecessary.
  • Intercom door release system: This system includes an electronic door opener that allows visitors to be granted entry through the substation. It is most often used in large residential, commercial and industrial applications, as it improves convenience. The intercom buzzer with door release button is typically located at the entrance of a building. When pressed, it sends a signal to the substation. The occupant in control can then speak with the visitor and press a button that allows guests to be granted access.

Types of entry intercom systems by technology

Intercom door entry systems can also be categorized based on the type of technology used. The most common types are:

Audio intercom system

Typically used in residential applications, an audio door intercom system includes a master station and one or more substations. The audio door entry intercom system allows communication between the master station and substation via a microphone and speaker.

Video intercom system

With a video component, video door intercom systems allow users to view visitors via a small built-in camera at the door before granting them access. They are far more secure than audio intercoms, as occupants can visually verify a visitor’s identity before granting access.

Telephone intercom systems

Another type of door entry intercom system is a telephone intercom, which uses a landline or mobile phone to connect the master station and substation. The way it works is that visitors choose the phone number of the person they want to speak with on the keypad, and their call is routed through the intercom. If the occupant wants to grant them access, they enter a code or press a dedicated button in an app.

The all-in-one intercom security system from Avigilon

  • 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

Types of intercom entry systems by connectivity options

Intercom systems can also be categorized based on their connectivity options, which refers to how the master station connects to the substations. Intercom systems can be:

Wired intercom system

Wired intercoms use a hardwired connection between the master station and substations through cabling that has to be installed in walls or ceilings. This hardwired intercom system also requires cabling to provide power to the components.

Larger facilities with multiple substations have to be installed by professionals because of the complexity involved in wiring the system. As a result, installation costs and time can be high, as well as the cost of maintenance due to the need for regular repairs and troubleshooting. The system can also be challenging to expand because it means installing more wires. 

Some systems aren’t suitable for larger applications and might have to be changed completely. For example, a 3‑wire intercom system is usually recommended for buildings with fewer than 30 units, while a 4‑wire system can be used for as many as 100 units. If you’re running a 3‑wire intercom system and need to expand to more than 30 substations, you might have to switch out the whole system.

Despite the limitations, a 2‑way wired intercom system is a very secure and reliable option, as it is not subject to interference or signal loss.

Wireless intercom system

Wireless intercoms are becoming increasingly popular due to their convenience and low maintenance costs. They use Wi-Fi or Bluetooth technology to connect the master station and substations, eliminating the need for cabling.

The installation process is usually straightforward, as wireless components are easier to install than wired systems. This helps reduce installation costs and time, as well as the costs associated with future maintenance.

However, the signal strength can be affected by walls, electrical devices and other wireless systems, leading to signal loss or interference. For this reason, it is crucial to ensure good signal quality before installing this type of system. If the signal is poor in some areas of the building, installing additional antennas or repeaters might be necessary to ensure a strong and reliable connection.

Bandwidth is another issue that should be considered with wireless door entry intercom systems. A 2‑way wireless intercom system transfers audio, video and other data between the master station and substations, meaning it requires a certain amount of bandwidth. Therefore, it is vital to ensure that the chosen system can handle the facility’s data transmission needs.

While a wireless door entry system is generally more convenient and cost-effective than a wired system, it can also be vulnerable to security risks such as hacking. The system must be well-protected with access control and encryption to combat this risk.

Despite these concerns, a front door wireless intercom system offers a wide range of benefits, including:

  • Smartphones can be used to replace substations, making these front door intercom wireless systems cost-effective for any application.
  • Less time and cost associated with installation and maintenance.
  • Flexibility to expand or relocate the system as needed.
  • The system can be installed throughout a building without concerns over cabling issues.
  • Highly convenient, as users can access these remote intercom systems from wherever they are using the Internet.

Networked intercom system

Networked intercoms are a relatively new type of system and are becoming increasingly popular due to their flexibility. They use an IP network connection to connect the master station and substations, allowing them to be located in other buildings or sites without detriment to the audio or video quality. Users can access the system remotely, making it possible for operators to manage the system from anywhere. 

The installation process for this type of system is also relatively simple and can be easily expanded or relocated by adding or removing components from the network. The main downside is that a reliable Internet connection must be available at all times to ensure a strong and secure connection.

An Internet door entry intercom system can store data locally or in the cloud, providing an additional layer of security. Cloud-based door intercom systems also offer a range of features, such as live streaming, access control and automated responses.

Additionally, a web-based door intercom system can be integrated with other technologies, such as access control and video surveillance, allowing for a more comprehensive security solution.

Hardwired intercom system

Mains hardwired door entry intercom systems are a low-cost option ideal for residential applications. This type of system uses the mains electrical system as the communication medium rather than radio waves or Wi-Fi. It doesn’t require additional wiring or cabling and can be installed quickly and easily.

Telephone or smartphone intercom system

An intercom with phone system has to be connected to the phone line or a mobile phone network to work. The phone is the communication medium for this type of intercom system and can be either wired or wireless.

The most common application is in large residential buildings, as they are highly convenient, especially smartphone-based systems. The convenience, coupled with the increased use of smartphones, has led to more widespread commercial and enterprise applications.

What is the best intercom system?

The best entry door intercom system depends on the individual application and budget. There are a number of factors to consider when selecting an intercom system, such as:

1. Location

It is essential to know the exact location where the intercom system will be installed to determine its feasibility and suitability for the given environment.

For example, if the intercom is to be installed in a residential building, a mains-hardwired intercom system may be the most cost-effective and simple solution. On the other hand, an Internet-based system may provide more flexibility and features for a building.

Another consideration is whether it will be an outdoor intercom system or an indoor system. Outdoor entry intercoms require more robust weatherproofing, while indoor systems are much simpler to install and maintain.

Both types of systems require a power source, and it is essential to ensure an available electrical outlet or access to the mains. The location must also be considered when opting for an Internet intercom system, as access to a reliable Internet connection is necessary.

2. Range

The range is a critical factor to consider when selecting an intercom system, as it will determine the most suitable type of intercom system for a particular building. The intercom’s range will determine the size of the area it can cover, and different systems offer different ranges.

For example, hardwired intercom systems are typically suitable for small to medium-sized residential buildings, while Internet-based intercoms can cover larger areas. However, a wireless intercom may be the best option if the system has to cover a large area or multiple buildings.

Wireless systems are more flexible than wired systems, as they do not require additional cabling or wiring. Additionally, they can provide two-way communication over longer distances and offer the flexibility to be installed in different locations.

On the other hand, if the intercom is going to be used in a smaller area, a wired system may be more economical. Wired intercom systems are typically less expensive than their wireless counterparts and can be used in areas with limited access to electrical power or spotty Internet signals.

3. Security

Security is another essential factor to consider when selecting an intercom system. This will determine the level of access control necessary for the given application.

In some residential applications, a complex intercom system with stringent access control may not be necessary. However, a robust intercom system with extensive security features will likely be required in commercial settings or areas with restricted access. In such cases, the intercom system can be integrated with other access control measures, such as biometric or smart card readers. This ensures that only authorized personnel are given access to the premises.

4. Ease of installation

Intercom system installation can be a time-consuming and expensive process. Selecting an intercom system that is easy to install can help reduce the overall installation costs.

For wireless intercom systems, this will depend on the size and complexity of the system. Choosing a plug-and-play system can help reduce the installation time. Some manufacturers offer systems that are pre-programmed and ready to use once installed. This eliminates the need for setting up the intercom system and can help reduce installation costs.

Wired intercom installation will often be more complex than a wireless system and may require the services of an experienced electrician or technician. Wired systems require physical cables to be run from each intercom station to the central hub. The type of cables depends on the system, but may include twisted pair, coaxial, or fiber optic cables. Installing the wires can be time-consuming and expensive.

Another aspect to consider is the Internet connection for Internet-based intercom systems. Many experts recommend opting for a wired connection to the Internet, even if the rest of the system is wireless, to ensure a more reliable connection.

5. Number of substations and users

When selecting an intercom system, it is vital to determine the number of substations and daily users that will be part of the system. This will affect the type and size of the chosen intercom system and the cost. For example, a two-way intercom system may be suitable for small residential applications with only one or two users. However, more advanced systems with multiple substations will be required for larger applications, such as offices.

The number of users will determine the type and size of the central hub. This will need to accommodate the additional users and provide enough power for all substations.

6. Durability and flexibility

Durability is another important factor to consider when selecting an intercom system. The system should be able to withstand daily use without deteriorating. This includes being able to withstand temperature and humidity fluctuations, as well as power outages. The device should also be constructed from durable, high-quality materials to ensure it can withstand the rigors of daily use for many years.

Flexibility should also be considered when choosing an intercom system. If the system will be installed in a large building with a significant number of users, it is important to select an intercom system that allows for future expansion. A wireless intercom system may be the best option, as it allows for easy expansion without rewiring the entire system. Additionally, some manufacturers offer modular systems that can easily be expanded as needed.

7. Video features

Some intercom systems include the ability to send and receive video, as well as audio signals. Video features can provide added security, allowing users to visually identify visitors before granting access. Some systems offer features such as motion detection and night vision.

However, it is important to note that video intercom systems can be more expensive and may require additional installation time. The benefits of these features should be weighed against the cost before purchasing.

8. Integration capabilities

Intercom systems can be integrated with other technologies, such as video security and access control. This can enhance security, as users can easily monitor who is entering and leaving a building.

Some intercom systems can be integrated with automation systems, allowing for automated responses to specific events. For example, the intercom can be programmed to open a door when an authorized user enters the premises.

Modern intercom systems can be integrated with smartphones, allowing users to control the system and access video feeds remotely. This can provide added convenience and security, as users can monitor their homes or business from anywhere in the world.

Most smartphone apps allow users to customize the system to their specific needs. This can include setting schedules for when the system is active and creating user profiles for each substation. It can also save on purchase and installation costs because less hardware is required. However, it is important to ensure that the system is compatible with a range of smartphones and operating systems.

Integration capabilities vary from system to system, so it is essential to consider which features are most important. Users should ensure that the system is compatible with existing hardware and software.

9. Convenient access methods

Depending on the application, an intercom system that offers multiple ways to gain access to the property may be beneficial. A combination of keypads, cards and other access methods can provide added security and convenience.

Touchless and keyless door entry  access are becoming increasingly popular because they are more convenient than traditional access methods. They also provide better security, as they limit the risk of unauthorized access.

Touchless access refers to any form of access that does not require the authorized user to touch the gate or door. It usually involves an automatic door opener and a sensor that is activated when the authorized user approaches.

Contactless access refers to an access method where operators can give visitors access without the need to be physically present. Someone could be in another country and still be able to open the security gates or doors via an app.

An intercom system should also include features that allow users to easily grant access to visitors or contractors. This can consist of temporary codes sent via text message, as well as remote access from a smartphone.

10. Cloud-based management systems

The latest trend in intercom systems is the use of cloud-based services. This allows users to store audio, video and other data on a remote server, providing access from anywhere with an Internet connection.

Cloud-based services provide extra security and convenience, as users can access the system from multiple locations. Some systems offer features such as automated updates and remote troubleshooting.

However, it is vital to ensure that the cloud-based service is secure and reliable before selecting a system. Some services may require users to pay monthly fees or purchase additional storage space.

Another factor to consider is whether the intercom system can manage multiple access points. This can be beneficial in larger buildings, where access from parking garages or other outbuildings is required.

In these cases, ensuring that the system can handle multiple simultaneous users and provide access to the correct substations is vital. Some systems allow users to customize their access points to only access certain areas of the building or property.

These features can provide added convenience and security, as users can easily set up access to specific areas of the building or property.

Buyer’s guide: The best entry intercom systems for your property

When selecting an intercom system, the total cost of ownership should also be considered. This includes the upfront costs for hardware and installation, and ongoing costs for maintenance, upgrades and replacements. It is also essential to consider the cost of integrating the system with other technologies. Some intercom systems may also require users to pay monthly fees for cloud-based services or additional features.

An intercom system is meant to protect a property and is a significant investment, so choosing a reputable provider is necessary. It is worth researching the provider and their products before making a purchase. Reading genuine customer reviews can also help to identify any potential problems. Also confirm that the provider offers reliable customer support, regular updates and maintenance. The company should provide a warranty in case of any malfunctions or defects.

Intercom systems are a convenient way to provide access control and security for residential or commercial properties. By considering factors such as range, wireless or wired installation, cloud-based services, integration capabilities and total ownership cost, users can select the best system to meet their needs.

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

Avigilon Video Intercom Reader Pro

When choosing the best entry intercom security system with a video component for your property, an all-in-one edge device can simplify installation and management. Avigilon’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, cloud-native intercom system has AI-powered voice for enterprise-grade call routing suitable for commercial offices and multifamily residential installations, and features an optional QR code-based directory that syncs with your user database. 

Run on intuitive cloud-based software, the mobile-optimized interface allows fully remote management, complete with HD mobile video monitoring, remote unlock capabilities and backward compatibility with existing security infrastructure. 

Video Intercom Reader Pro device specs and features: 

  • Single-touch intercom doorbell and voice-activated call routing through responsive AI
  • Mobile video calling, on-demand playback and remote unlock capabilities
  • Two-way audio with echo and noise cancellation
  • 5 MP high-definition camera that supports WDR on an ONVIF Profile S and T compliant video platform
  • Easy snap-in installation with single PoE cable and adjustable camera angle
  • Multi-technology reader built-in for touchless entry with mobile app, tablet app, Smart Watch and key card support
  • IP65 rated for outdoor use

Avigilon H4 Video Intercom 

The H4 Video Intercom is designed to help you streamline the management of access at secure entry points. Featuring a 3 MP fisheye camera and a high-performance intercom, this solution works with Avigilon Unity video management software to allow you to easily identify and communicate with visitors before remotely granting access.

For enhanced situational awareness, you can use the Avigilon Unity VMS to quickly search for a visitor using Avigilon Appearance Search, which incorporates the unique characteristics of a person’s face to search for the same individual, even if items such as their clothing change over time.

To help keep internet connectivity costs down, the H4 Video Intercom leverages HDSM SmartCodec™ technology to optimize compression levels for regions in a scene to help maximize bandwidth savings.

H4 Video Intercom specs and features:

  • Offers exceptional image quality in scenes with both very bright and very dark areas, plus adaptive IR and exposure settings based on scene conditions 
  • Built-in audio capabilities enables operators to activate audio talk down
  • Optimizes compression levels for regions in a scene to help maximize bandwidth savings
  • On-device SD or MicroSD memory card storage for offline functionality during an outage
  • ONVIF compliant to allow integration with other security solutions
  • Relay I/O connection allow you to configure input/​output actions and alarms
  • SIP provides greater flexibility in routing incoming calls, enables integration with phone exchange and provides decreased downtime
  • IP66/7 weather rating and IK10 impact rating for vandal resistance

Comprehensive intercom system reviews

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