Complete Guide to Door Phones: What They Are & How They Work

 

 

A door phone is a building entry system that lets visitors call a resident, tenant, or staff member from the front entrance so they can speak with the visitor and grant access remotely. Door phone systems are commonly used in apartment buildings, condos, offices, and gated properties where owners and operators need a simple way to manage entry.

But as building technology has evolved, many buyers are reevaluating traditional door phones. Older systems often rely on costly in-unit hardware, limited functionality, and outdated infrastructure, while newer solutions offer video calling, mobile app access, remote management, and easier retrofits.

In this guide, we’ll explain how door phones work, break down the main types of systems, and compare them with modern alternatives so you can choose the right solution for your property.

Navigate this guide:

• What is the best alternative to door phones?
• Replacing your door entry phone system
• What is a door phone?
• Types of door phones
• How a door phone works
• Limitations of door phone systems
• Door phone FAQs

 

 

What is the best alternative to door phones?

The ButterflyMX video intercom system offers enhanced hardware and user-friendly software. Over 15,000+ customers have already installed ButterflyMX in their buildings. Simply put, the intuitive nature of this next-generation access control system is highly rated, state-of-the-art, and convenient.

More features of the ButterflyMX smart video intercom system include:

• Sleek design. The ButterflyMX IP video intercom has a 156° wide-angle camera that captures a broad picture of the surrounding area. Furthermore, it has an aesthetically pleasing design instantly increases your building’s curb appeal.
• Highly-rated mobile app. The part of the system tenants will use the most is the mobile app. Moreover, the ButterflyMX intercom makes it easy for tenants to use their phone app as a credential. Moreover, the intercoms are already equipped with WiFi.
• Integrations with other systems. The ButterflyMX intercom system easily integrates with a number of smart lock brands, which makes it easy for residents to control access from one app.
• Remote property management. The cloud-based ButterflyMX system simplifies property management. This means building staff can integrate their property management software with the intercom to streamline building administration processes.

 

Watch how ButterflyMX works:

 

Features of the best door phone alternatives

Doorbell phones might’ve gotten the job done at the turn of the century. But today, they don’t cut it anymore. Instead, IP video intercoms compete with today’s and tomorrow’s technological advances.

The top features to seek in IP video intercoms are:

• Transmission Control Protocol/Internet Protocol (TCP/IP) connectivities: IP video intercoms that use TCP/IP offer more complex features, such as digital access credentials to authorized guests.
• Highly-rated mobile app: The part of the system that tenants will use the most is the mobile app. So, make sure to choose a system that has an app with high ratings on the Apple and Google Play app stores.
• Integrations with other systems: The intercom operating system should integrate with other building automation systems, such as smart locks and thermostats. That way, residents can control all aspects of their apartment building from one app.
• Remote property management: Pick a cloud-based system to simplify property management. That way, building staff can integrate their property management software with the intercom to streamline building administration processes. With cloud-based systems, staff can monitor access control permissions and troubleshoot system bugs from anywhere.

 

Replace your door entry phone system with ButterflyMX

If you have a door phone system installed at your property, you’re long overdue for a replacement — try ButterflyMX instead.

ButterflyMX’s smart video intercom makes property access simple. With an easy-to-use mobile app and features that improve the access experience for residents and property staff, ButterflyMX beats out any doorbell phone system.

 

 

What is a door phone?

A door phone is the in-unit hardware component of a door entry system, an electronic device that facilitates communication and property access between visitors and tenants.

Also known as doorbell phones, door phones are placed inside individual apartment units. Typically, these devices are mounted on the wall and include buttons or a handset for tenants to listen and speak with guests at the building’s front entrance.

This in-unit device connects to outdoor hardware installed at the property entrance. Some systems operate on a telephone landline, while others transmit data wirelessly via the Internet. Newer systems also support video, allowing tenants to visually confirm visitors’ identities before letting them inside.

 

Components of a door phone system

Although there are various types of door phone systems, they all consist of three essential components:

• Outdoor station: The outdoor panel is installed near the front door or gate. Sometimes called an intercom doorbell, it includes a series of buttons, each button connecting to a specific unit’s doorbell phone. Additionally, the outdoor panel has a microphone and speaker.
• In-unit devices (phones): In-unit devices are the system’s actual “phone” component. They’re installed inside every unit within a property. Many door entry phones include wired telephone handsets. Tenants press either ‘9’ on the keypad or a designated ‘door open’ button to unlock the door remotely.
• Door release: You’ll need a door release mechanism with either an electric or magnetic lock so tenants can remotely open the door once they’ve granted visitors access.

 

Types of door phones

The term ‘door phone’ refers to various door entry phones, including wired and video options. In the past, doorbell phones exclusively meant in-unit landline telephone systems. But today, there are also wireless door entry phone solutions.

The three main types of door phone systems are:

• Wired
• Wireless
• Video

 

Wired door phones

Wired systems require each in-unit device to be physically connected to the outdoor panel via telephone lines. Once a guest presses a button on the entry door phone intercom, that sends a signal to call the phone in the corresponding unit.

The biggest drawback of wired doorbell phones is that they’re one of the most expensive entry systems to install and maintain. And if one system component breaks, you may have to replace all the devices in every apartment unit.

 

Wireless doorbell phones

Wireless door phones, such as WiFi video doorbell phones, enable wireless connection via an Ethernet cable, cellular network, or Bluetooth. Today, connecting wireless door entry phones to the internet is most common. Also called IP door phones, wireless doorbell phones follow the Internet Protocol, which enables them to send signals via the Internet.

Since IP phone intercoms can transfer more data than wired systems, they often support video calls. Modern IP doorbell systems connect to tenants’ smartphones, allowing them to open the door or gate using their phones.

To provide more complex functionality, IP door entry phones use other internet-related protocols:

• Voice over Internet Protocol (VoIP): VoIP enables audio transfer between devices over the Internet. VoIP doorbell phones can transfer larger amounts of data than wired systems can.
• Session Initiation Protocol (SIP): SIP door phones work with VoIP technology to deliver video data and ensure that data syncs up with the system’s audio.

 

Video door phones

Video door phone systems operate with video calling, allowing tenants to see who’s at the door before opening it for them. The in-unit doorbell phone includes a screen to display video footage of visitors.

Modern video doorbell phone systems operate on VoIP and SIP to transfer audio and video data over the internet between visitors and tenants.

Wireless video doorbell phone systems may or may not include a physical, in-unit phone. While some do, the best systems replace in-unit hardware with tenants’ own smartphones. As a result, these IP video doorbell phone systems come with a mobile app that tenants can download on their smartphones, enabling them to answer visitor calls and remotely open the door from their phones.

 

How a door phone works

A doorbell phone facilitates audio-only or video calls between visitors and tenants in a commercial or multifamily building. If the system is a video door phone with an intercom, it supports video calls — which means tenants can see who’s requesting access.

Using the device installed at the entryway, visitors search for the tenant they’re visiting within the system’s directory. Then, the visitor presses the corresponding button, which rings the tenant’s in-unit entry phone.

Finally, the tenant answered the call on the doorbell and spoke with the visitor before granting them entry. If the in-unit device has a numeric keypad, the tenant presses ‘9’ to open the door or gate for the guest. Other doorbell phones will have a designated ‘door open’ button.

 

Limitations of door phone systems

At their core, door phone systems are synonymous with telephone entry systems. Although not all doorbell phone systems need to be connected to telephone lines, most still require extensive wiring throughout the entire building. But that’s not the only limitation of doorbell phones.

The four biggest limitations of door phone systems are that they:

1. Require complicated and expensive hardware
2. Don’t have cloud-based software
3. Can’t be retrofitted for the modern-day
4. Lack robust security and convenient features

 

1. They require complicated and expensive in-unit hardware

Many traditional door phone systems rely on physical hardware installed inside every apartment or office suite. That setup increases installation complexity because each unit may need wiring, mounting, and ongoing maintenance.

From an operations standpoint, in-unit hardware makes repairs and replacements more time-consuming because staff or vendors often need access to occupied units. For residents, the experience can feel outdated and inconvenient compared with systems that route calls to a smartphone. From an upgrade perspective, hardware-heavy systems are harder to modernize because replacing or removing devices across multiple units can be disruptive and expensive.

 

2. The system isn’t cloud-based

Older door phone systems are typically not cloud-based, which means many tasks must be handled on-site. Updating directories, troubleshooting issues, or changing access settings may require staff to be physically present at the property.

Operationally, that can slow response times and increase administrative burden, especially for teams managing multiple buildings. For residents, limited remote management can lead to longer delays when access issues arise. When it comes to upgrades, a lack of cloud connectivity makes it harder to integrate newer software tools or support more efficient building operations over time.

 

3. They can’t be retrofitted for the modern-day

Traditional door phones are often tied to legacy wiring and older infrastructure. In occupied properties, this can make replacements or system improvements more complicated than expected.

The operational impact is significant because retrofit projects may require more labor, coordination, and time on-site. For residents, installation work can be disruptive if technicians need repeated access to units or common areas. The upgrade implication is that older systems may limit a property’s flexibility, making it harder to adopt newer entry technologies without a more involved replacement project.

 

4. The system lacks robust security and convenient features

Basic door phone systems were designed primarily for two-way audio communication. While that may still work in some buildings, many residents now expect features like video calling, mobile app access, delivery management tools, and a more seamless guest entry experience.

Operationally, fewer built-in features can mean more manual work for staff and less visibility into building access activity. For residents, the experience may feel less convenient and less secure, especially when they cannot see visitors, manage access remotely, or review entry events easily. From an upgrade standpoint, properties using feature-limited systems may eventually need to replace them to meet modern expectations.

 

Door phone FAQs

• Are door phone systems still used in apartment buildings?
• Can a door phone system work without a landline?

 

Are door phone systems still used in apartment buildings?

Yes, door phone systems are still used in some apartment buildings, especially older properties with legacy entry infrastructure. However, many owners and operators are replacing them with newer systems that support video, mobile access, and remote management.

 

Can a door phone system work without a landline?

Some older door phone systems rely on telephone lines, but many newer systems work over the internet instead. IP-based door entry systems can route calls through software or mobile apps rather than through a traditional landline connection.