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Updated Oct 20, 2023

What Is Non-Fixed VoIP?

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Jeff Hale, Business Operations Insider and Senior Analyst

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Not every small business has a brick-and-mortar location. Even with companies that do, employees may not be onsite. So how do customers talk to you and your staff? A non-fixed VoIP system, which is a type of business phone system, may be the solution.

What is VoIP?

Voice over Internet Protocol (VoIP), also known as “IP telephony,” is a technology primarily used to deliver voice communications in packets of data over the internet. With non-fixed VoIP, you can communicate on a phone through an internet connection instead of through physical wiring (like a landline). This lends itself well to businesses without physical locations or companies with distributed call centers. Instead of communicating through a desk phone or another type of phone tied to a particular location, you can make and receive calls from anywhere through a mobile phone, computer or tablet. 

When you have multiple non-fixed VoIP numbers set up, you can digitally connect them to form a virtual phone system for your business. While the person on the other end of the call likely won’t be able to distinguish between a non-fixed VoIP phone call and a regular call, there are a number of pros and cons to weigh when determining which type of VoIP technology is the best fit for your business, employees and customers.

What is a non-fixed VoIP phone number?

A non-fixed VoIP number is often referred to as a “virtual phone number.” They can be assigned to a specific user or device as opposed to a physical address, which is required for fixed VoIP lines and landlines

All you need to get a virtual phone number is an email address and sometimes a payment method, making it far easier to obtain than a fixed VoIP number or a traditional landline. Even better, in some instances, non-fixed VoIP phone numbers don’t require payment, making them even simpler to get and use. 

What’s more, non-fixed numbers can be created with any area code, which can give callers on the other end the impression that you have a local presence. The familiar local area code increases the likelihood that a customer or sales lead will answer your call. [Find out more reasons why VoIP makes sense for businesses.]

What is the difference between a fixed VoIP and a non-fixed VoIP number?

The biggest difference between a fixed VoIP and a non-fixed VoIP number is the requirement of a physical address for the fixed option. Both allow calling through the internet, but you still need an actual location for fixed VoIPs. In contrast, businesses with a non-fixed VoIP phone number or system don’t need to be tied down to a specific location.

Non-fixed VoIP calling also differs from fixed VoIP in the way the phone number is assigned. In a non-fixed scenario, your VoIP number, or “virtual number,” is assigned to you and can be used to make and receive VoIP phone calls from anywhere in the world as long as the user has a decent connection to the internet. With a fixed VoIP service, your phone number is assigned to a physical location – think of a traditional landline phone setup. 

As far as the person on the other end of the line is concerned, both VoIP calling options provide clear and reliable communications as long as there is a strong internet connection to support the non-VoIP side of the call. 

Fixed VoIP phone numbers

  • This is an actual phone number tied to a physical location or address.
  • The area code is assigned based on the associated address.
  • Location services, like when a call needs to be traced, are easy to use and reliable.

Non-fixed VoIP phone numbers

  • This is a virtual number tied to a user or device.
  • The area code can be selected to match any desired location.
  • Location services are difficult to use.
Key TakeawayKey takeaway

The physical address requirement is the most significant difference between a fixed VoIP and a non-fixed VoIP phone number.

Who typically uses a non-fixed VoIP?

Call centers, managed service providers, messenger apps and businesses with remote workforces all frequently use non-fixed VoIP services to make phone calls. In each of these use cases, the ability to provide a local number for incoming and outgoing calls is incredibly valuable for customer convenience and trust. Businesses that need to communicate with people around the world often rely on non-fixed VoIP phone systems to build large teams nationally and internationally.

The ability to quickly build an international customer service and support team without paying the significant overhead for multiple office buildings and business phone systems across the globe makes this flexible option incredibly useful and cost-efficient. The option to spread your staff across the country or around the world also increases the speed at which you can build and staff a large virtual call center without relying on job applicants in one location near a physical office. [Learn more factors to consider in our guide to choosing a business phone system.]

Messenger apps that use the internet to connect phone calls and send both MMS and SMS messages also use non-fixed VoIP to handle voice communications. Apps such as WhatsApp, Facebook Messenger, Google Voice and Skype rely on non-fixed VoIP numbers to handle voice communication from within the app. However, some service providers and financial institutions won’t accept non-fixed VoIP numbers as a business’s official line of communication.

What are the pros and cons of non-fixed VoIP numbers?

Non-fixed VoIP numbers are easy to attain, move and set up through any number of VoIP service providers. Their low barriers to entry and flexible features have made them equally useful for companies growing quickly and for scammers engaged in fraudulent activities. Here are the biggest pros and cons of this kind of phone system.


  • You can call from anywhere. These phone numbers are not tied to a specific address and can therefore be assigned with any area code to provide the appearance of a local presence. This means your call recipient will always see a local number on their caller ID when you contact them, regardless of where you are.
  • You can set them up quickly. Beyond the simplicity of getting your first number, it’s also very easy to add and remove additional virtual phone numbers. Companies with seasonal businesses or those experiencing rapid growth can easily expand their virtual call centers and sales floor capabilities at a moment’s notice without worrying about committing to a long-term contract for phone services or other costly overhead required with a physical office.
  • Rearrangements are easy. Changing the assigned user or device with a non-fixed VoIP number is very easy. This means HR professionals and managers can quickly reassign phone numbers to new users and devices as the need arises. 


  • Scammers use them a lot. The biggest knock against non-fixed VoIP numbers has nothing to do with the technology itself. It’s that these numbers are not only too easy to get in some situations, but they also don’t require the level of personal information that could be used to identify the owner in the case of fraud or other crimes. Additionally, thanks to their frequent use for robocalling and other phone-based scams, many spam blockers will filter or flag virtual phone numbers to protect users on the other end.
  • They’re bad for emergency situations. When you call 911 with a non-fixed number that’s not tied to a physical address, your call may not be routed to the correct emergency dispatch center. Because non-fixed VoIP calls cannot be easily traced, getting emergency services such as the fire department or police to your location may be difficult. If your company uses non-fixed VoIP numbers, it’s important to let your staff know to always use their personal numbers on their mobile phones to contact emergency services.
  • You can’t use them in all situations. Many organizations consider these numbers unreliable for official communication. That means you may not be able to use your virtual phone number as a key point of contact on an account for anything significant, such as banking and other business services. 

As you consider whether non-fixed VoIP phoning is right for your company, make sure you check out our best business phone systems, including our Nextiva review and our RingCentral review.

Did You Know?Did you know

Some service providers can tie a physical address to your non-fixed VoIP number for use in emergencies.

What are the pros and cons of fixed VoIP numbers?

Still not sold on a non-fixed VoIP number for your business? Fixed VoIP phone numbers provide a few very strong advantages over their fully virtual counterparts with minimal added expense. In fact, their requirement to be tied to a physical location brings several valuable benefits, although some cons do remain.


  • Authenticity: There is a higher level of trust associated with a phone number tied to a physical location. Fixed VoIP phone numbers can project credibility and will have an easier time bypassing spam filters designed to block unwanted phone calls.
  • Location services: Fixed VoIP phone numbers are assigned to physical locations with specific addresses. This means any emergency calls made to 911 will be routed to the correct call center for proper dispatch. It also means calls can potentially be traced in fraud cases.
  • Advanced features: Fixed VoIP phone numbers and service providers can include more options for special features, such as audio and video conferencing, SMS and MMS, and online faxing. All of these make it easier for call centers and customer services departments to communicate with clients while tracking their progress and results more efficiently. 


  • Physical address: Your phone number’s area code must match your company’s physical location. While many virtual businesses may be able to use the home address of the company’s owner or a P.O. box as their physical address, some financial institutions and other companies will not accept a P.O. box as a physical address.
  • More expensive setup: These systems require more time to install and are therefore typically more costly to set up. In comparison, most non-fixed VoIP services don’t have any setup fees and will allow you to bring your old desktop phone equipment if possible.
  • International calling cost: While not the case with every provider, long-distance and international calling typically cost more with fixed VoIP. However, in many international calling situations, a fixed VoIP number or traditional landline is the only way to reach callers in other countries due to strict spam-blockers designed to protect end users from scams. For companies that handle both international and domestic calls, it can make sense to use both fixed and non-fixed VoIP numbers depending on the specific situation.

Why does VoIP matter?

Communication is paramount in a small business. Whether you’re keeping in touch with employees or reaching out to customers, it’s important to have open, reliable lines of communication. For many companies, that means relying on non-fixed VoIP to talk via phone regardless of location. Whether you ultimately decide to go with fixed or non-fixed VoIP, make sure everyone on your team knows proper phone etiquette. That’s essential for small businesses regardless of which phone system you choose.

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Jeff Hale, Business Operations Insider and Senior Analyst
Jeff Hale is a communications and content marketing expert with extensive experience leading teams as a managing editor. He has deep knowledge of B2B communications technologies, including business phone systems and customer relationship management (CRM) software. Jeff is also an entrepreneur who knows the realities of launching and managing a small business, where he serves as a Content Director and SEO Consultant. In his role as an entrepreneur and professional, Jeff has identified new market opportunities for Fortune 500 clients and developed communications strategies and digital branding for tech startups and small businesses. Jeff holds a Bachelor’s degree in English from the University of California, Irvine, and an MBA from Chapman University.
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