What is VoIP & how does it work?
Voice over Internet Protocol (VoIP) is a technology that uses the internet to make phone calls. The analogue signals of the speaker are converted into digital signals and transferred to the VoIP service provider via the internet. They are then converted into digital packets before being sent to the receiver.
With the news that the UK’s old system of landline will be phased out by December 2025, many businesses have shifted to VoIP phones. And logically, it is the right thing to do. At the most basic level, you just need an internet connection along with a device (mobile phone or computer) to make a call using VoIP.
What is a landline phone & how does it work?
A landline phone uses physical copper wires to transmit voice signals between telephones. When a call is made, the voice signals are converted into electrical signals that travel to the public switched telephone network (PSTN). They are then routed to the recipient’s phone before being converted back into audio. It is to be noted that you require a physical handset on both sides for the landline to work.
Landlines provide reliable communication, especially in areas with limited mobile coverage or even during power outages, however, they are becoming less popular with the rise of internet-based devices.
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What Does The UK PSTN Switch-Off Mean for Your Business?
One thing you should know if your business is still operating on a traditional landline. The UK’s Public Switched Telephone Network (PSTN), the copper-wire telephone infrastructure that has been in service since Victorian times, is being permanently turned off.
BT has now officially pushed back the original PSTN switch-off deadline from December 2025 to 31 January 2027. But BT has strongly encouraged its business customers to migrate long before the end of 2026, claiming that it can take between 6 to 9 months to transition. And if you haven’t planned yet, then you should start your planning now.
Why Is It Being Switched Off?
The PSTN is a legacy, analogue network that is strewn across the ground, over copper wiring and cannot deliver modern communication requirements. The PSTN is increasingly vulnerable and constantly on the verge of failure.
In summary, switching to a fully digital, IP-based network, which VoIP offers, is not only cheaper but also safer and wiser.
What Does This Affect?
Most business owners assume that the switch-off only applies to their desk telephones. In truth, it has a far wider impact than just calls. This includes any device connected to an analogue or ISDN line.
Here’s a brief overview of the potential impact on your business:
| What’s Affected | Why It Matters |
|---|---|
|
Desk Phones (Analogue/ISDN) |
They will not work after the cut-off date. |
|
ADSL and FTTC Broadband |
You will need to upgrade to full-fibre broadband. |
|
Security Alarms and CCTV |
They will not work if they use PSTN connectivity. |
|
Fax Machines |
Will not work over copper lines. |
|
Card Payment Terminals |
Some older card payment terminals use PSTN. |
|
Lift Emergency Telephone Lines |
It should be converted to digital options |
Can I Keep My Phone Number?
Yes. Number porting should allow you to keep your existing phone numbers, at least most of the time. Porting typically takes 7 to 14 working days, and as the demand for migration increases until 2026, porting queues are likely to stretch, meaning that acting now is highly recommended.
Key Takeaway: The PSTN switch-off is not simply a troublesome technical issue; it represents a challenging deadline, and all UK businesses need to be ready. The good news is that transitioning to VoIP is the way forward, as it is a cost-effective solution, and when many companies think about switching systems, it’s far simpler than they usually expect.
How To Switch From Landline To VoIP: Step-By-Step Process?
Transitioning from a traditional landline to VoIP doesn’t need to be complex. Follow these steps, and your business will be up and running on a contemporary phone system with little to no disruption:
Step 1: Audit Your Current Setup
Take note of your current telephone lines, broadband connections, alarms, CCTV, fax machines, door entry systems, and card payment terminals. During this process, many businesses discover lines they were previously unaware of, so please be thorough.
Step 2: Inspect Your Internet Connection
The quality of your VoIP calls directly depends on the state of your broadband connection. Test your connection’s bandwidth, latency and packet loss under real-world conditions.
Generally, a stable VoIP connection requires at least 100 Kbps per call, a rate that is well within most modern business broadband offerings.
Step 3: Make a Decision Between VoIP Solutions
There are two lead routes: the Hosted VoIP/Cloud PBX (your provider does the work in the cloud; this is most common for SMEs, really quick to set up, and there’s little hardware required) or SIP Trunking (if you already have an on-site PBX that you don’t want to replace, SIP trunking simply connects your conventional phone systems and the internet instead of them using PSTN). For the majority of UK SME businesses, hosted VoIP is the easiest and cheapest solution.
Step 4: Port Your Existing Number
When switching to VoIP, you don’t have to lose your existing business phone number. If you were using a landline, then number porting will let you transfer your current number to the VoIP service provider. Porting can take 7 to 14 working days, so be sure to plan the process in advance and avoid any gaps in service.
Step 5: Configure Your VoIP System
After creating an account and getting your number ported, set up your system. This usually involves configuring voicemail, call forwarding rules, auto-attendant menus, and ring groups. Most VoIP service providers offer a user-friendly online dashboard, eliminating the need for experts.
Step 6: Train Your Team
Though VoIP systems are quite intuitive, a brief onboarding is super helpful. Guide your team on how to make and receive calls, access voicemail, and download the mobile app, as well as advanced features such as call transfer or video conferencing.
Step 7: Test It Before You Go Live
Make sure to keep both systems running before disabling your old landline. Make practice calls, listen to the sound quality, and ensure call forwarding and voicemail are functioning properly. Once you are satisfied, you can completely disconnect your landline.
VoIP vs Landline Cost Breakdown
The cost is one of the biggest drivers behind UK businesses looking to switch to VoIP, and the figures are hard to ignore. Here is a practical comparison of what a typical business can expect to pay for each system:
| Cost Area | VoIP | Landline |
|---|---|---|
|
Installation |
Little to none, as you can use your existing internet connection |
£100 to £500+ (depending on number of lines) |
|
Monthly Cost Per User |
£7 to £25/user/month |
£12 to £35/line/month |
|
Hardware |
Optional |
Mandatory desk phones and PBX hardware (£50 to £200 each) |
|
International Calls |
Low (unlimited minutes instead of charge per minute) |
Very pricey |
|
Domestic Calls |
Most plans offer unlimited calls |
Usually charged per minute |
|
Maintenance |
Managed by provider |
On-site maintenance needed: engineer fees apply |
|
Scalability |
Instantly add users (no extra setup cost) |
Requires new physical line and hardware per user |
|
Advanced Features |
Included in plan (auto-attendant, call recordings and call analytics) |
Often a paid extra or not available |
Example: 10-Person Business In 12 Months
The table below shows what the actual cost differences would be for a small UK business with 10 employees:
| Factor | VoIP | Landline |
|---|---|---|
|
Per Line/User Monthly Cost |
£150 (10x£15) |
£300 (10x£30) |
|
Annual Line Cost |
£1,800 |
£3,600 |
|
Hardware |
£0 to £300 |
£1,000 to £2,000 |
|
Maintenance |
Included in plan |
£1,500/year (estimated) |
|
Approximately Annual Total Cost |
£1,800 to £2,100 |
£5,100 to £7,100 |
Note: The numbers will vary, but the trend is true across the board: VoIP saves around 40% to 60% against a traditional landline system, and even more as your team scales up.
VoIP vs Landline for business: Detailed Comparison
Is it worth switching to VoIP? Read the points below and decide whether VoIP is better for your business or landline.
| Feature | Description |
|---|---|
|
Security |
Landline calls are not encrypted while VoIP phone calls are encrypted and the system comes with advanced security features, too. |
|
Cost |
The installation and running costs of the VoIP system are less than landline the phone system. |
|
Reliability |
Landline phones remain functional in power outages while VoIP services do not. |
|
Features |
VoIP offers more features and accessibility than a landline phone system. |
|
Scalability |
Since you don’t need physical phone lines for VoIP, thus it is easier and quicker to scale. |
|
Sound quality |
The sound quality of landline phones is traditionally better than VoIP but that is changing with the betterment of codec technology. |
|
Requirement of equipment |
A VoIP phone system doesn’t need dedicated desk phones or phone lines but landline phone systems require both to work. |
|
Freedom of different phone numbers |
You can only have one fixed local phone number for your landline phone but in the case of VoIP, you can choose a phone number from anywhere in the world. |
1. Security
Landline phone calls are routed through the PSTN, which is not encrypted, making them vulnerable to interception. VoIP phone calls, on the other hand, are usually encrypted which means they are more secure.
But make sure you choose a reliable VoIP provider that offers effective security features like call monitoring system, authentication measures, segmentation of voice traffic, high-level encryption, multiple servers and security certifications.
2. Cost
Businesses that choose to switch from landline to a VoIP system will save money on installation and monthly charges as well.
VoIP providers offer different monthly packages that you can choose from depending on your needs. Landline providers, conversely, usually offer a fixed rate per line.
Lowest monthly cost of VoIP in the UK: £7/month per user
Lowest monthly cost of landline in the UK: £12/month per line
It’s to be noted that this VoIP rate includes extra features like auto-respondent, call centre analytics and video sharing which landlines don’t offer.
Also, the installation cost for VoIP service is essentially zero, as you can utilise your existing cellphone or computer to handle calls. Conversely, with landlines, an additional phone line and desk phone are required, adding to the minimum installation expenses.
Moreover, the calling charges for VoIP phone service are lower than landline phones. There are good VoIP providers in the UK offering packages that allow unlimited domestic calls and affordable international calls. On the other hand, landline phone providers charge a per-minute cost for domestic calls and high costs for international calls.
3. Reliability
Contrarily, the landline phone system boasts greater reliability compared to VoIP. Landline phones remain functional even during power outages or internet disruptions. In contrast, VoIP relies entirely on internet connectivity; thus, call management becomes impossible if the internet connection is lost.
However, it’s worth noting that adverse weather conditions tend to impact landline phones more than VoIP phones. This is because the majority of internet lines are buried underground, whereas telephone lines are susceptible to damage from wind and rain above ground.
So, realistically, it’s a trade-off that you have to analyse.
4. Features
One of the biggest differences between VoIP and landline is the number of features they offer.
This is where VoIP beats landline hands down. While landline systems offer basic functionalities like caller ID, call waiting, call forwarding and voicemail, VoIP systems offer a variety of features. Some of them are mentioned below.
- Voicemail transcription: The voicemails get converted into texts so call agents can reply to the text without listening to lengthy voicemails.
- Auto attendants: The calls from the customers are received by automated greetings and instructions before being diverted to the right department (or agent).
- Ring group: It’s a group of phone numbers that ring simultaneously. They work on a first-come, first-served model. This shortens the call queues and hold times.
- Call centre analytics: This system monitors call data and arranges it for better understanding and tracking. This includes call duration tables, usage reports, sentiment analysis and predictive analysis. You can generate customised reports, agent performance charts and business trends using them.
- Video conferencing: Remote and in-house team members can hop onto video meetings, share their screens and execute in-meeting chats to improve collaboration and productivity.
- Ticketing: The incoming phone calls from customers get converted into tickets and sorted in the inbox for better prioritisation and streamlined workflow. The agents can then respond to these queries using email, one-click calling, texting or video.
Furthermore, you can integrate the VoIP phone system with other software applications like customer relationship platform (CRM) to improve the workflow and performance.
5. Scalability
Scaling a VoIP phone system is speedy and involves less hassle. To add a new line, all you have to do is call your VoIP provider. They will add a virtual extension through the software and you can then assign that extension to your employee.
When it comes to landlines, each new employee requires a new physical line. While you can generate additional extensions, you’re limited to the maximum capacity set by your private branch exchange system. Moreover, you have to have a separate desk phone for every team member you add.
All this makes scaling the landline phone system expensive and time-consuming.
6. Sound quality
One of the benefits of landline vs VoIP has long been that landlines offer better sound quality since the signals carry more audio information. But that is changing with the introduction of HD codecs being used in VoIP phone systems.
Thanks to this technology, the previous issues of VoIP sound being jittery are quickly being resolved.
7. Requirement of equipment
A landline phone system needs dedicated phones that have to be connected to a specific port. That means each employee needs to have a separate desk phone which he can’t even take around the office. Which means the scope of mobility is limited.
In addition, you also need phone lines to connect each landline desk phone to the PBX system.
As for the VoIP phone system, it can be set up on any internet-connected device (laptop or phone). The employees can take their phones anywhere to manage calls and you don’t need to invest in a separate phone desk for each of them as well.
This is particularly important for remote workers. Even if they’re not at their work desks, they can easily take phone calls on the go, provided they have a stable internet connection.
8. Freedom of different phone numbers
Since every landline phone connection is linked with a specific address, thus you’ll receive a specific local phone number when using a landline phone. For example, you’ll receive a phone number with 020 dialing code if your business is based in London.
With the VoIP phone system, you can choose a virtual phone number from anywhere in the world because they are not tied to a local address. This means that you could use a dialing code of 212 (New York) while running your business from London.
This helps your business feel local no matter where you’re reaching, pulling in more customers. For instance, you can get a VoIP number of Australia and chat with Australian customers.
VoIP And Landline: Pros And Cons: At A Glance
It’s worth having a clear, honest picture of what VoIP does well and where it has shortcomings compared to a traditional landline before making any decision.
VoIP Pros and Cons
| Pros | Cons |
|---|---|
|
Monthly costs are lower than landlines. |
Call quality varies based on your internet. |
|
Functions on any device connected to the internet. |
An internet connection is required. |
|
Very scalable; a new user can be onboarded in minutes. |
It will not work during a power cut. |
|
Extra features included in the plan are call recording, video calls, call analytics, and many more. |
It requires team training before use. |
|
Good for remote and hybrid teams. |
|
|
Virtual numbers: you can choose any UK area code. |
|
|
CRM and business software integrations. |
|
|
Fast implementation: the system is up and running within hours. |
|
Landline Pros and Cons
| Pros | Cons |
|---|---|
|
Very reliable |
Costly to set up. |
|
Does not require broadband quality. |
Fewer features than VoIP. |
|
Common and easy to use. |
Cannot accommodate remote or hybrid employees. |
|
It works during a power cut. |
PSTN switch-off by January 2027. |
|
Consistent audio quality. |
It is complex and costly to scale. |
VoIP vs Landline: Which Is The Real Winner For Your Business
So, after considering cost, features, flexibility and the approaching PSTN switch-off deadline, the answer for almost every business in the UK is simple: VoIP is clearly a stronger long-term proposition.
Of course, every business is different. Here is a simple checklist to help you make a choice:
Choose VoIP If Your Business:
- Has a workforce of remote, hybrid, or multi-site employees
- Has a growing number of users and must add them quickly and at low cost
- Is looking to lower monthly phone payments without losing features
- Depends on capabilities such as call recording, auto-attendants, or CRM integrations
- Is still on a fixed line and needs to prepare for the PSTN switch-off
Continue using a landline (for now) if your business:
- Operate from one single, fixed location.
- Has very basic communication needs, such as inbound and outbound calls only.
- Is located in a region with little or slow broadband coverage.
And even if a landline still functions in your case, it is only a temporary solution. The closing-down of the PSTN is bigger than an upgrade; it’s a fundamental change for how UK businesses communicate.
Transitioning to a modern digital platform like VoIP is more than just preventing being cut off from your phone service; it also gives your business greater flexibility, tools that scale, and the ability to tailor how you communicate.
As in all technology transitions, the switch to VoIP is not without its fears. However, with the right VoIP provider, the transition is swift, inexpensive, and, more often than not, immediately useful. Companies that start early will be better positioned, networked, and equipped than those who wait until the deadline leaves them with no choice.
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FAQs
Yes, VoIP can work on a landline phone. What you need is a VoIP adapter. It plugs into a wireless router or wired modem. You have to enter the IP address on the VoIP adapter using an internet-connected device, follow the steps to configure it and finally plug your landline phone into it.
Yes, the traditional landline lines will be switched off by December 2025 and they will be replaced by digital lines that will use the internet to make and receive calls. But you can still use your landline to make calls. Your telephone provider will guide you about the necessary changes needed.
Although its benefits beat the cons, but some of the biggest disadvantages of VoIP include reliance on an internet connection, risk of hacking because of the internet transmission and no emergency calling support as the number is not linked to a physical address.
