What is non-fixed VoIP? A complete business guide

The ISDN is shutting down across Europe, the great cloud migration is underway, and your employees and customers are demanding a better user experience (UX).

To keep up, businesses are saying goodbye to on-premise telephony and welcoming Internet-based voice and emergency calling, or Voice over Internet Protocol (VoIP). 

Let’s take a deep dive into all things VoIP, so you feel confident and prepared in the non-fixed VoIP conversations you’ll find yourself in this year.

What is VoIP?

Voice over Internet Protocol (VoIP) is a technology that delivers voice communications in packets of data over the internet instead of physical landlines. 

VoIP phones, softphones, or analog terminal adapters (ATAs) rather than physical desk phones attached to copper lines.

How does VoIP work?

When you place a call using VoIP technology, your audio signal turns into data packets, and shifts back to an audio signal once it’s reached the destination. 

There are three steps to placing a call with VoIP: 

1. The voice is compressed into data packets, 
2. The data packets are sent over networks (like the public and private internet), and 
3. The packets arrive at the other end of the network and are converted back into voice.

Information about the caller (including the phone number and the caller name assigned to that VoIP phone number) is transmitted in the CNAM (Caller Name) tag. Then, the recipient’s device will display your CNAM information as part of caller ID.

Now that we’ve covered what VoIP is and how it works, let’s explore fixed and non-fixed numbers, and when these might be useful for your business. 

What is a non-fixed VoIP phone number? 

Non-fixed VoIP numbers are numbers that are assigned to a user with any geographical location, rather than a fixed physical address or device. Sometimes called “Virtual Phone Numbers,” you can order phone numbers for areas where your business isn’t located to create a local presence. 

Smartphones and communications apps (like Microsoft Teams and RingCentral) typically use non-fixed VoIP numbers. Think about it this way: if your employees or users are moving around, you don’t want their PSTN connectivity “fixed” to a singular address or device.

So if you have a hybrid or global workforce, non-fixed VoIP numbers let you match each employee’s phone number to your company’s number format. This makes sure each employee has a number (also known as a Direct Inward Dialing (DID) number) that matches their location without the need for physical phone lines.

What are the benefits of non-fixed VoIP?

Non-fixed VoIP numbers are widely used because of their flexibility and simple provisioning requirements. Today’s enterprise often uses non-fixed numbers because: 

1. They’re easy to manage. Because a non-fixed VoIP number is easy to provision and manage, businesses use non-fixed VoIP. They work whether you need new contact center numbers or a new employee has joined. Most business phone numbers through services like Microsoft Teams and RingCentral are non-fixed. If an employee ever leaves or you need to move numbers around, you can reassign non-fixed numbers in minutes. 
2. You can establish a local presence, globally. Because you can use any area code or country format, your employees and call centers can call customers and prospects with area codes that are familiar to them, regardless of location. Learn about local VoIP phone numbers.
3. You can scale up and down. Non-fixed VoIP allows businesses to quickly add new phone numbers as their teams expand, contract, or transition to working from home. 
4. They can lower costs. Because you don’t need to pay for a physical office location to link local numbers, you can lower overhead costs and shift from CAPEX to OPEX. You’ll also lower international calling costs with non-fixed VoIP numbers within the corresponding country. 

What are the downsides of non-fixed VoIP?

We’ve talked about why businesses love non-fixed VoIP. Now, let’s talk about the drawbacks. 

1. Additional emergency compliance requirements. While with a fixed VoIP device, there is always a known service address that can be used for emergency calling. When your employees call emergency services from a non-fixed VoIP number, public safety may need to take extra steps to determine the caller’s current dispatchable address. Without those extra steps, emergency responders may not have an accurate address to pinpoint your employees during a workplace emergency. 

2. Higher levels of fraud. Because a non-fixed VoIP number is so easy to get and hard to trace, they’re often used by telecom fraudsters and scammers. While the FCC and service providers have taken steps to mitigate fraud, spam, and robocalling, you can also report incidents to the VoIP provider. You can learn more about fighting telecom fraud here. 

What’s the difference between non-fixed VoIP and fixed VoIP?

Where a non-fixed VoIP isn’t tied to a specific location, a fixed VoIP phone number has a residential or business location tied to it. Most of the time, fixed VoIP numbers are assigned to analog devices found in offices, campuses, or hotel phone systems, and use multi-line telephone systems (MLTS). 

Why businesses choose fixed VoIP numbers

We’ve talked about the downsides of non-fixed VoIP numbers—let’s talk about how fixed VoIP can solve those problems. 

1. You can use caller ID. A fixed VoIP number is harder to get, making them more reputable and less likely to be used by fraudsters. They’re also identifiable with caller ID, so customers and prospects are less likely to think you’re spam.
2. Emergency responders have more location information. When an employee dials 911/112 from a fixed VoIP number, the call is associated with a specific location and can automatically route the emergency call to the designated public safety answering point (PSAP). You may need to take additional steps to fulfill FCC requirements, depending on your phone systems.

What are the downsides to fixed VoIP numbers?

There are times when using a fixed VoIP number just doesn’t make sense for your business or goals. 

1. International calling costs. Making long-distance calls are expensive if you have VoIP phone numbers with local area codes.
2. Less number flexibility. You can’t establish a local presence everywhere you have customers and prospects if your business expands beyond where you have offices since numbers are tied to your office locations.

However, remember that you can use both fixed and non-fixed VoIP numbers. In fact, large-scale enterprises often use both kinds of numbers, for different reasons. 

VoIP: Frequently asked questions

You asked, we answered—here are common questions around VoIP numbers, and our best answers! 

Can you text a non-fixed VoIP?

Yes! To text a non-fixed VoIP number, simply configure your number to send and receive SMS text messages. 

How do you find out who owns a non-fixed VoIP number?

Because there’s no physical address, it’s harder to track non-fixed VoIP numbers. VoIP numbers can also be moved to different users and devices, so the information you find might not be accurate. However, you can try using physical or digital phone records, or a caller ID database. 

How do you know if a number is fixed or non-fixed? 

You probably can’t, unless you go directly to the phone number provider. Non-fixed VoIP numbers look and act just like a fixed VoIP number, but you can perform a number lookup using CNAM to find data about the number’s owner. 

Wrapping things up: Fixed vs. Non-fixed VoIP

For global businesses with employees and prospects all around the world, using a non-fixed VoIP line is your best bet. It’s easy to set up, easy to adjust, and can improve your customer relationships with transparent, reliable connections.

Use this table as a quick reference when deciding what type of VoIP number to use: