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This connection to the Public Switched Telephone Network (PSTN) prevents a fixed VoIP number from being used in geographic locations other than the location where the number is assigned. Though, it’s worth noting that a fixed VoIP number can work without that connection to the PSTN.

But, even though a fixed VoIP number typically connects to the PSTN, calls to and from fixed VoIP phone numbers do not rely entirely on the PSTN. Typically, the call audio will travel on the PSTN for only a short distance before being converted into a digital signal for transmission over the internet.

This connection route may be a bit more complex than just using the internet or the PSTN to connect calls. But it’s actually a best-of-both-worlds situation.

Additionally, if you change your address, it’s much easier to take your fixed VoIP phone number with you than it is to move a classic landline.

Ultimately, fixed VoIP phone numbers are a way to get a phone number that’s trustworthy enough for any business use case, with the improved call quality and reliability of an internet connection.

How fixed VoIP Works

Even though a VoIP number functions the same as a traditional phone number, due to VoIP origination, VoIP numbers offers features that an ordinary number doesn't. Although a fixed VoIP number connects to the PSTN, a fixed VoIP phone number mostly uses the PSTN to establish the address assigned to the phone number.

Your VoIP phone may not connect to a traditional RJ11 phone jack (ethernet cables are more common), but it will connect to the PSTN connection in the building at some point before the signal is transferred to the internet.

Good VoIP providers work to minimize the time that call audio spends on the PSTN. The PSTN isn’t a very high performance network. So, ideally, VoIP carriers build their network to minimize hops on the PSTN. When a call to or from a fixed VoIP number is routed properly, the call will make one quick hop on the PSTN at the address where the fixed VoIP number is assigned—the rest of the connection is achieved using the internet.

How fixed VoIP differs from non-fixed VoIP

The obvious difference between a fixed and non-fixed VoIP phone number is that you can use a non-fixed VoIP number from just about anywhere in the world, whereas you can only use a fixed VoIP number from the location assigned to that fixed VoIP number.

However, this leads to other differences.

First, you must have a physical location in the country where you want to get a fixed VoIP phone number. For example, if you want a fixed VoIP phone number for the United States, you need to have a physical location inside the United States for that phone number. Conversely, non-fixed phone numbers can be provisioned from anywhere.

Then, since a fixed VoIP phone number must be assigned to an address, the process for provisioning a fixed VoIP phone number is a bit more involved than the process for getting a non-fixed VoIP phone number.

All you need to get a non-fixed VoIP phone number is an email address and a payment method. You need an address and a bit more personal information to provision a fixed VoIP number.

But, from the perspective of the end user, a fixed VoIP phone number looks and works the same as any other phone number.

The fixed VoIP market

The VoIP market is expanding rapidly across the world, which enables more connectivity and better global communication. What's driving the VoIP market?

As is the case with many tech advancements, the transition to VoIP is largely powered a convergence of falling costs and rising demands. It’s estimated that businesses could save as much as 50% by transitioning to VoIP services.

With the capability to initiate calls over wireless and cellular networks, VoIP solutions that meet the needs of the distributed workforce are more available and affordable than ever, which is a huge contributor to market growth.

The VoIP market also benefits from new global markets that are opening up as economies and infrastructures around the world improve.

Overall, the VoIP market is driven by the capability and flexibility of VoIP technology to facilitate core business processes at lower costs than pre existing solutions and the abundance of new markets and subscriber bases with very little market penetration.

Fixed VoIP phone number pros and cons

Fixed VoIP numbers require a bit more effort to provision, but there are reasons to use a fixed VoIP number instead of a non-fixed VoIP phone number. By the same token, there are use cases where a non-fixed VoIP number is a better option.

These are the benefits and disadvantages to consider:

Benefits of a fixed number

• Can be used for almost anything. Non-fixed VoIP phone numbers are often not accepted as contact phone numbers on accounts or as emergency contact numbers. Fixed VoIP phone numbers are considered just as trustworthy as landline phone numbers. So you can use a fixed VoIP phone number in most cases where a landline is required and in cases where a VoIP phone number is a better option.
• Better access to emergency services. Fixed VoIP phone numbers are easier to trace than non-fixed VoIP phone numbers, which enables emergency calls to be traced for faster EMS response. And the associated address enables emergency calls to be properly routed to the nearest emergency call center.
• More versatile than a landline phone number. Typically, landlines cannot receive text messages. Fixed VoIP phone numbers can be configured to send and receive both SMS and MMS text messages. Additionally, it’s easier to set certain caller ID information for a fixed VoIP phone number than it is to change the caller ID info on a landline. Some countries block calls from non-fixed VoIP phone numbers or have restrictions on how you can use non-fixed VoIP numbers. Fixed VoIP phone numbers are usually not subject to the same restrictions.

Disadvantages of a fixed number

• Not as easy to provision as a non-fixed VoIP phone number. You need an address and some associated information to get a fixed VoIP phone number. It’s not difficult to get a fixed VoIP number, but it is not ideal if you need to quickly add a lot of phone numbers.
• Subject to similar geographic restrictions as a landline. A fixed VoIP phone number must be formatted for the country where the associated address is located. It’s not as simple to make international phone calls from a fixed VoIP phone number as it is from a non-fixed VoIP number. And there can be calling fees for making long distance and international calls.

When to consider fixed VoIP

Although a fixed VoIP phone number isn’t perfect for everything, there are certain use cases where a fixed VoIP phone number is definitely the best option. Here are some examples:

Primary phone numbers for physical business locations

Even if you have several phones in your building that have non-fixed VoIP phone numbers, it’s a good idea to have at least one fixed VoIP phone number for any business location.

This works as a business phone number for creating business accounts with vendors and banks and also ensures that you have reliable contact with emergency services. There may also be local regulations that require a landline or fixed VoIP phone number for any physical business location.

All in all, it’s wise to have at least one fixed VoIP phone number, whether you are a small business or large corporation.

Secure voice communication

Fixed VoIP numbers are more difficult to spoof than non-fixed VoIP phone numbers, and the connection to the physical location provides a more predictable connection path. It’s easier to encrypt calls from fixed VoIP phone numbers (though a good VoIP provider can encrypt calls from non-fixed VoIP phone numbers, too).

Non-fixed VoIP phone numbers can produce secure calls as well, but fixed VoIP phone numbers are better in business sectors like banking and cybersecurity, where you need a phone number with a high degree of authenticity and security.

Managed Service Providers (MSP)

MSPs that provide telecom services should keep some fixed VoIP phone numbers in their inventory—or work with a telecom carrier that can supply fixed VoIP phone numbers—for clients who need the authenticity and functionality of a fixed VoIP phone number. Without access to fixed VoIP phone numbers, your MSP will struggle to offer telephony services like emergency calling.

For more information on how to get a fixed VoIP number, talk to one of our experts.

Want to compare fixed VoIP options? Join our subreddit community: https://www.reddit.com/r/Telnyx/

For some businesses, a fixed VoIP number may not just be a better choice, but a necessity.

Why? A fixed VoIP phone number is assigned to a physical address, similar to a traditional landline. A non-fixed VoIP number, however is assigned to a user and can be used from any geographic location. In short, a fixed VoIP sacrifices some flexibility for more authenticity, which is often important for businesses.

What is fixed VoIP?

A fixed VoIP phone number is a VoIP number that has been assigned to a particular physical address. Fixed VoIP numbers connect through the internet, just like non-fixed VoIP phone numbers. However, a fixed VoIP number usually connects to the public switched telephone network (PSTN) through a SIP trunk. To learn more about how SIP trunking and VoIP work together, read our blog post.

This connection to the Public Switched Telephone Network (PSTN) prevents a fixed VoIP number from being used in geographic locations other than the location where the number is assigned. Though, it’s worth noting that a fixed VoIP number can work without that connection to the PSTN.

But, even though a fixed VoIP number typically connects to the PSTN, calls to and from fixed VoIP phone numbers do not rely entirely on the PSTN. Typically, the call audio will travel on the PSTN for only a short distance before being converted into a digital signal for transmission over the internet.

This connection route may be a bit more complex than just using the internet or the PSTN to connect calls. But it’s actually a best-of-both-worlds situation.

Additionally, if you change your address, it’s much easier to take your fixed VoIP phone number with you than it is to move a classic landline.

Ultimately, fixed VoIP phone numbers are a way to get a phone number that’s trustworthy enough for any business use case, with the improved call quality and reliability of an internet connection.

How fixed VoIP Works

Even though a VoIP number functions the same as a traditional phone number, due to VoIP origination, VoIP numbers offers features that an ordinary number doesn't. Although a fixed VoIP number connects to the PSTN, a fixed VoIP phone number mostly uses the PSTN to establish the address assigned to the phone number.

Your VoIP phone may not connect to a traditional RJ11 phone jack (ethernet cables are more common), but it will connect to the PSTN connection in the building at some point before the signal is transferred to the internet.

Good VoIP providers work to minimize the time that call audio spends on the PSTN. The PSTN isn’t a very high performance network. So, ideally, VoIP carriers build their network to minimize hops on the PSTN. When a call to or from a fixed VoIP number is routed properly, the call will make one quick hop on the PSTN at the address where the fixed VoIP number is assigned—the rest of the connection is achieved using the internet.

How fixed VoIP differs from non-fixed VoIP

The obvious difference between a fixed and non-fixed VoIP phone number is that you can use a non-fixed VoIP number from just about anywhere in the world, whereas you can only use a fixed VoIP number from the location assigned to that fixed VoIP number.

However, this leads to other differences.

First, you must have a physical location in the country where you want to get a fixed VoIP phone number. For example, if you want a fixed VoIP phone number for the United States, you need to have a physical location inside the United States for that phone number. Conversely, non-fixed phone numbers can be provisioned from anywhere.

Then, since a fixed VoIP phone number must be assigned to an address, the process for provisioning a fixed VoIP phone number is a bit more involved than the process for getting a non-fixed VoIP phone number.

All you need to get a non-fixed VoIP phone number is an email address and a payment method. You need an address and a bit more personal information to provision a fixed VoIP number.

But, from the perspective of the end user, a fixed VoIP phone number looks and works the same as any other phone number.

The fixed VoIP market

The VoIP market is expanding rapidly across the world, which enables more connectivity and better global communication. What's driving the VoIP market?

As is the case with many tech advancements, the transition to VoIP is largely powered a convergence of falling costs and rising demands. It’s estimated that businesses could save as much as 50% by transitioning to VoIP services.

With the capability to initiate calls over wireless and cellular networks, VoIP solutions that meet the needs of the distributed workforce are more available and affordable than ever, which is a huge contributor to market growth.

The VoIP market also benefits from new global markets that are opening up as economies and infrastructures around the world improve.

Overall, the VoIP market is driven by the capability and flexibility of VoIP technology to facilitate core business processes at lower costs than pre existing solutions and the abundance of new markets and subscriber bases with very little market penetration.

Fixed VoIP phone number pros and cons

Fixed VoIP numbers require a bit more effort to provision, but there are reasons to use a fixed VoIP number instead of a non-fixed VoIP phone number. By the same token, there are use cases where a non-fixed VoIP number is a better option.

These are the benefits and disadvantages to consider:

Benefits of a fixed number

• Can be used for almost anything. Non-fixed VoIP phone numbers are often not accepted as contact phone numbers on accounts or as emergency contact numbers. Fixed VoIP phone numbers are considered just as trustworthy as landline phone numbers. So you can use a fixed VoIP phone number in most cases where a landline is required and in cases where a VoIP phone number is a better option.
• Better access to emergency services. Fixed VoIP phone numbers are easier to trace than non-fixed VoIP phone numbers, which enables emergency calls to be traced for faster EMS response. And the associated address enables emergency calls to be properly routed to the nearest emergency call center.
• More versatile than a landline phone number. Typically, landlines cannot receive text messages. Fixed VoIP phone numbers can be configured to send and receive both SMS and MMS text messages. Additionally, it’s easier to set certain caller ID information for a fixed VoIP phone number than it is to change the caller ID info on a landline. Some countries block calls from non-fixed VoIP phone numbers or have restrictions on how you can use non-fixed VoIP numbers. Fixed VoIP phone numbers are usually not subject to the same restrictions.

Disadvantages of a fixed number

• Not as easy to provision as a non-fixed VoIP phone number. You need an address and some associated information to get a fixed VoIP phone number. It’s not difficult to get a fixed VoIP number, but it is not ideal if you need to quickly add a lot of phone numbers.
• Subject to similar geographic restrictions as a landline. A fixed VoIP phone number must be formatted for the country where the associated address is located. It’s not as simple to make international phone calls from a fixed VoIP phone number as it is from a non-fixed VoIP number. And there can be calling fees for making long distance and international calls.

When to consider fixed VoIP

Although a fixed VoIP phone number isn’t perfect for everything, there are certain use cases where a fixed VoIP phone number is definitely the best option. Here are some examples:

Primary phone numbers for physical business locations

Even if you have several phones in your building that have non-fixed VoIP phone numbers, it’s a good idea to have at least one fixed VoIP phone number for any business location.

This works as a business phone number for creating business accounts with vendors and banks and also ensures that you have reliable contact with emergency services. There may also be local regulations that require a landline or fixed VoIP phone number for any physical business location.

All in all, it’s wise to have at least one fixed VoIP phone number, whether you are a small business or large corporation.

Secure voice communication

Fixed VoIP numbers are more difficult to spoof than non-fixed VoIP phone numbers, and the connection to the physical location provides a more predictable connection path. It’s easier to encrypt calls from fixed VoIP phone numbers (though a good VoIP provider can encrypt calls from non-fixed VoIP phone numbers, too).

Non-fixed VoIP phone numbers can produce secure calls as well, but fixed VoIP phone numbers are better in business sectors like banking and cybersecurity, where you need a phone number with a high degree of authenticity and security.

Managed Service Providers (MSP)

MSPs that provide telecom services should keep some fixed VoIP phone numbers in their inventory—or work with a telecom carrier that can supply fixed VoIP phone numbers—for clients who need the authenticity and functionality of a fixed VoIP phone number. Without access to fixed VoIP phone numbers, your MSP will struggle to offer telephony services like emergency calling.

For more information on how to get a fixed VoIP number, talk to one of our experts.

FAQ

What is fixed VoIP and how does it work?

Fixed VoIP is a voice service where your number is bound to a registered service address for consistent location and emergency support. In business deployments, fixed VoIP operates over your internet connection but is tied to that address for billing and compliance.

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

Fixed VoIP is anchored to one service address, while non-fixed numbers can be used from multiple locations or devices. That portability defines non-fixed VoIP and enables rapid provisioning for remote teams or temporary sites.

Is fixed VoIP better for emergency calling?

Yes, because a fixed number includes a registered address that supports accurate E911 routing. Proper E911 VoIP configuration ensures emergency services see the right address when a caller cannot share location.

How does fixed VoIP affect compliance and fraud risk?

Binding numbers to a service address creates stronger account verification and reduces abuse compared to disposable, nomadic numbers. It also simplifies regulatory obligations like address validation and lawful intercept readiness in many regions.

What do I need to set up fixed VoIP at my office?

You need reliable broadband, VoIP-capable phones or softphones, and a router that prioritizes voice traffic with QoS. A basic VoIP network includes SIP trunks or a hosted service, internal LAN segmentation for voice, and E911 address registration for each location.

What are the main types of VoIP services?

Most providers classify VoIP as on-premises, hosted, or hybrid, each with different control and cost profiles. Fixed numbering can be used across these models if the service is registered to a specific address.

When should a business choose fixed VoIP instead of non-fixed?

Companies with permanent offices, compliance needs, or on-site teams benefit from stable addressing, E911 readiness, and reduced fraud exposure. Fixed numbers also simplify porting, directory listings, and location-based features like local trunking.