
As organisations rush to move to VoIP and beat the PSTN switch off deadline, we answer 19 of your most common questions about VoIP telephony.
How does a VoIP phone system work?
VoIP, or Voice over Internet Protocol, describes a group of technologies which enable phone calls to be made over the internet. This is a modern alternative to the traditional PSTN (Public Switched Telephone Network) service which uses copper wires to connect each phone.
With PSTN, when your call connects it effectively opens a private pathway between the two phones along the copper wires.
VoIP technology works differently. It breaks up your call into “packets” of data. These are then transmitted through the internet and rearranged back into their original form when they arrive at the destination phone.
When was VoIP invented?
The idea of breaking up a voice conversation into packets of data, to be transferred via the internet, dates back to the early days of ARPANET (the forerunner of the internet) in the 1970s.
In the 1990s technology had moved on sufficiently for VoIP to be feasible for commercial use. Skype, which uses VoIP, was launched in 2003. Over the following years a proliferation of VoIP services came onto the market.
Do you still need a PBX for VoIP?
A PBX, or Private Branch Exchange, is the switch system which connects two telephones. Essentially, it’s the technology which looks at the number you dialled and figures out which phone it needs to put you through to.
Another form of the PBX is the PABX, Private Automated Branch Exchange. This is typically used by companies and connects multiple telephones to multiple lines, allowing communication internally as well as with outside callers.
This functionality is still required for VoIP, however it doesn’t need to be a physical system located in your business. In a hosted VoIP phone system the PABX is, effectively, in the cloud.

What’s the difference between hosted and on-premises VoIP phone systems?
Hosted, or cloud, VoIP systems are increasingly popular. They involve a third party (eg ITS) hosting your phone system via a virtual PBX in the cloud. The individual users within your organisation connect to the cloud via the internet.
On-premises, or private, VoIP systems require a central control unit (usually a PABX) to be installed within the business premises. This connects your phones/computers to the internet via a SIP Trunk protocol.
While more costly to set up and maintain, on-premises solutions can offer advantages to larger corporations in terms of scalability and security. For smaller businesses, a hosted VoIP system is often a better option. Find out more.
How do you set up a VoIP phone system?
Assuming you already have broadband connectivity, it should be a straightforward process to migrate from a traditional business phone system to VoIP.
If you opt for a Hosted VoIP system then you will simply need to switch to VoIP handsets, or install the VoIP app on computers/mobile phones. Your existing internet connection will then be used to connect you to the cloud and the PSTN.
With an on-premises VoIP system, additional work will be required to install your central control unit (PABX) and the SIP Trunk which will connect this to the internet.
How much does a VoIP phone system cost?
A VoIP phone system will almost always be cheaper than a traditional phone system.
Infrastructure costs, for example, are less because you’re simply expanding your use of the existing internet connection.
You can avoid costly hardware purchases by using PCs with headsets, rather than desk handsets. Or simply use existing mobile phones to access VoIP.
Maintenance costs are also reduced by the simplified infrastructure and reduction in the number of devices required.
Are VoIP calls free?
It depends on the contract you have. In some cases you will pay a monthly subscription and all calls are free. In others, you may pay a lower monthly fee and then a small charge for some or all calls.
Contact us for advice on the best contract for your needs.
Are VoIP calls secure?
With any internet-connected device there is a risk of hacking attempts and VoIP is no different.
However, VoIP is still a very secure method of communication as the networks are constantly monitored and protected. An on-premises VoIP installation will provide additional peace of mind.
What’s the difference between VoIP and Unified Communications?
Unified Communications is an evolution of VoIP.
Unified Communications bring together all aspects of business communications (phone, fax, video, chat, email, etc) in a single online application. VoIP provides the framework which Unified Communications sits on.

Can our current phone number be transferred to VoIP?
Yes, in all but a very few cases, you can keep your current phone number, or numbers, when your organisation transfers to VoIP. This includes 0800 and other non-regional numbers.
This is done through a process called ‘porting’.
Do VoIP phone users have to have a phone handset?
No, phone handsets are optional for VoIP users. There are a couple of alternative solutions: you can make calls through an app on your mobile phone or call via your computer with a headset or microphone/speaker combination attached.
Do VoIP phones need to be attached to a computer?
No, VoIP handsets are available which work independently of a computer, connecting directly to the internet either using wifi or an ethernet cable.
Does VoIP work from mobile phones?
Yes, the vast majority of VoIP phone systems will provide you with an app to enable you to make calls from your mobile, so long as you have internet access.
Can VoIP be used for call centres?
Yes, absolutely. VoIP technology is a low cost and highly scalable solution for call centres. All the functionality you need is available, such as queuing, call recording and dialler integration.

Are VoIP phones easy to use?
Yes. If you install VoIP desk handsets then these will operate in the same way as any traditional phone handset.
Using VoIP from a computer is very intuitive. You simply access the keypad from your computer screen and use your keyboard or mouse to enter the phone number you wish to call. A similar method is used to call from mobile phones using VoIP.
What are the benefits of a VoIP phone system?
VoIP phone systems offer businesses low cost subscription and call charges. But this isn’t the only advantage of VoIP.
The systems are highly scalable and, particularly with a hosted solution, accessible from anywhere and any device that has an internet connection. They also support the introduction of Unified Communications, bringing together all your communication needs within one intuitive application.
VoIP phone systems are as feature-rich as their traditional counterparts, including functions such as call waiting, call transfer, voicemail, etc.
What are the disadvantages of a VoIP phone system?
Firstly, you need to have a stable internet connection for VoIP to work well. This isn’t an issue for most businesses, but those in more rural situations may find that VoIP isn’t reliable enough for their needs.
The process by which VoIP transmits data, breaking it up into little ‘packets’, can sometimes cause issues of latency and jitter if the packets are delayed during transmission or not put back together correctly. Good internet connectivity, cabling and router set up should minimise these issues.
Is Skype VoIP?
Yes, Skype is an early provider of VoIP technology. However, Skype is a closed network, meaning you can only call other Skype users. Today most VoIP phone systems allow you to call any other phone numbers, whether they are on VoIP or traditional phone lines.
Will VoIP replace traditional telephony?
Yes. In fact the PSTN is being switched off in the UK in 2025, at which point every phone user, business or home, will need to move to a digital connection.
The PSTN is reaching the end of its life and becoming increasingly difficult and costly to maintain.
Ofcom – The future of fixed telephone systems.
Analogue Telephone Adapter devices are available which would enable you to continue using your existing phone system through the digital service. However, this is short-term thinking and the best solution would be to embrace the switch to VoIP and all the advantages it can bring.
Start your move to VoIP
Switching to a VoIP phone system is a fantastic opportunity to reassess your communication needs and ensure that they are right for your organisation today and in the future.
We provide a range of VoIP hosted and on-premises solutions, including Unified Communications. Working in partnership with you, we’ll find the best solution for your requirements and budget. Call us on 0800 316 2970 to find out more.
Discover how we helped Buckmore Park move from their legacy infrastructure to an on-premises VoIP phone system in Medway.