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Is a Four-Line Phone System Right for Your Business?

Kiely Kuligowski
Kiely Kuligowski
Staff Writer

What is a four-line phone system, and how do you know if you need one?

  • A four-line phone system is a type of multiline phone system that provides lines in groups of four.
  • They can be a great option for small businesses, but are limited by coming only in four-line groups.
  • Consider your business's current and future needs to determine if a four-line system is right for you.

A four-line phone system is a popular option for many businesses looking to increase productivity, communication and efficiency. A four-line phone system is a unified communications tool that allows businesses to easily transfer calls and communicate both within and outside of the company. There are many types of business phone systems available that offer a variety of features and capabilities, so you're sure to find one that suits your business's needs.

What is a four-line phone system?

A four-line phone system is a type of multiline phone system that runs four analog (or landline) phone lines through your office. The lines can be internal or external. Internal lines allow employees in your office to communicate with each other, while external lines allow communication with customers, vendors or anyone else outside the office. If you require more than four lines, most systems will provide the option and the hardware to connect and service additional phones in groups of four.

Four-line phone systems differ from traditional phone systems in that they enable multiple parties to be on the phone simultaneously, whereas traditional phones only send audio data between two parties at once.

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How does a four-line phone system work?

A four-line phone system works in a similar way to a traditional one-line phone. Packets of voice data are sent over telephone network wires to recipients. All four lines run together on the same wire and receive the same calls, creating a system between the four phones.

Four-line phone systems are created via an extension that enables three other phones to be attached to the line. This extension is usually cordless, which enables the second, third, and fourth phones to be placed away from the first phone, allowing employees in each four-line group to have phones at their desks rather than all together.

How to know if your company needs a four-line phone system

Because a four-line system is a subset of a multiline phone system setup, a more specific set of circumstances is required to justify the choice.

For instance, a business needing a general multiline phone system might be an entrepreneur who wants to split their personal and business lines, a small business with two or more people who need constant access to a telephone, or a business with a high volume of calls at certain times.

A business looking for a four-line system, however, might have four or more people who need near-constant access to their phones, or perhaps a team of four that consistently need to be on calls together from their own desks.

You might also choose a four-line system based on the number of employees you have and their unique needs – for example, if you have a small business with a handful of employees and want to have multiple lines for different purposes, such as two lines for employee use, one line for a specific team, and one line for general business access, a four-line system would be a good option.

Four-line systems, as the name suggests, only come in groups of four, so you might be required to scale up by four whenever you need to add a line.

Features to look for in a four-line phone system

There are multiple key features you should look for when deciding on a four-line phone system. Some features may be included in your package, though more advanced features may need to be purchased as add-ons.

  • Do not disturb. Do not disturb sends all incoming calls directly to voicemail without the phone ringing. This feature can be helpful when you're in important meetings or when you cannot answer the phone.

  • Call transferring. This feature allows you to transfer calls either internally to someone else in your multiline system or to an external number like a sales or call center.

  • All page/intercom. Paging allows you to speak to all phones at once via the speakerphone, while the intercom feature lets you make announcements or inform other employees about a waiting call.

  • Mute and volume control. Mute and volume control allows you to mute, increase or decrease the volume of your speakerphone, phone audio or ringer.

  • Hold. Hold functionality varies per phone system, but some allow you to set customizable music to play while the caller is on hold.

  • Caller ID. Caller ID allows you to see who is calling, whether you choose caller ID, which displays the number of the caller, or caller ID with name, which displays the number and name of the caller. This can help you identify which calls are important or which are spam.
  • Speakerphone. Speakerphone can be helpful if you need to be hands-free while you're on the phone, or if you need a quick and easy way to conference in someone who is physically in the room with you during a call.

  • Voice mail. This allows callers to leave you a message if you have missed their call.

  • Automated attendant. Auto attendant is an advanced feature that greets callers and provides them with an employee directory or information.

  • Texting. Another advanced feature, texting services allow you to use your existing landline number to text customers on their mobile phones.

Pros and cons of a four-line phone system


The biggest pro of four-line phone systems is their capabilities – they allow a variety of solutions for all sorts of businesses. No matter how your business functions, you can make a four-line system work in your favor. But because there are many feature packages and support options to choose from, it is important that you do your research and explore all of your options so you choose the right business phone solution for your business.

Another main draw of four-line systems is their low cost. Costs may be higher if you need to purchase new equipment for your employees, but many multiline phone systems are shifting to internet-based models that host all data in the cloud and send call information entirely over the internet, which helps keep costs lower than traditional phone lines.

Modern four-line phone systems offer a host of communications and productivity-boosting features, like auto attendant, conferencing and do not disturb, and allow employees to easily receive and transfer phone calls both within and outside your organization. These features can increase efficiency in larger businesses and give smaller businesses a boost of professionalism by having an effective phone line.

Four-line systems are easily scaled and flexible, which means they can grow as your business does. You will need additional hardware from your provider or phone company, including cables, wired or wireless adaptors, or an expansion kit that supports multiple phone handsets from one phone jack.

The systems are also highly secure and reliable, with some providing data encryption services in your package and battery backup to provide service in the event of a power outage or internet connection issue.


The major con of four-line phone systems is that they are restricted to groups of four, which can be detrimental if your business has a four-line system and only needs to grow by one line. In this case, you would likely need to explore other options, such as VoIP phone systems that provide an internet-based phone number or a single extension.

Multiline phone systems are also dependent on cables and hardware, which can be difficult and costly for companies that do not have the required equipment, such as a headset or corded phone for each employee, or lack access to phone jacks.

Four-line phone systems can only be used with a traditional desk phone, which is becoming an increased detriment as the business world moves to mobile and flexible communication.

A four-line phone system would not be the ideal choice for a company whose employees frequently travel or work remotely.

Image Credit: jacoblund / Getty Images
Kiely Kuligowski
Kiely Kuligowski
Business News Daily Staff
Kiely Kuligowski is a business.com and Business News Daily writer and has written more than 200 B2B-related articles on topics designed to help small businesses market and grow their companies. Kiely spent hundreds of hours researching, analyzing and writing about the best marketing services for small businesses, including email marketing and text message marketing software. Additionally, Kiely writes on topics that help small business owners and entrepreneurs boost their social media engagement on platforms like Facebook, Twitter and Instagram.