October 16, 2020


  What are ISDN, PSTN and VoIP?

  Everything you need to know about The Big Switch Off.

–  The benefits of VoIP.

What do the phones look like in your business?

It’s almost guaranteed you’ll use one of three different kinds of telephone system in your business.

There haven’t been many major changes in the way we receive calls in the last 30+ years. How calls are distributed in offices has seen advancements but the phone lines themselves have stayed the same.

That’s set to change in the near future. No longer will businesses be able to use traditional phone lines because BT are switching them off in 2025. In the industry it’s being referred to as ‘The Big Switch Off’.

Of course, this doesn’t mean we’ll be unable to communicate. The solution is already here and many businesses have already adopted VoIP or Voice over Internet Protocol as their cloud-based telephony solution.

So why should you move? We look at that and more in this post.


For the uninitiated the above acronyms may be confusing. As far as most people are concerned, they don’t need think about these things. They just pick up the phone.

You may already know what these mean, but if not…

Let us explain. PSTN or Public Switched Telephone Network is the basic phone line that you have running to your home and some businesses too. Calls are distributed from an exchange elsewhere or on your premises.

If you are using a PSTN line, it cannot be used for any other purpose whilst a call is being made. This is traditional telephony and is delivered by copper wiring.

ISDN or Integrated Services Digital Network delivers digital communication via phone lines and used to be the main way we received the internet.

It has much broader telephone functionality than PSTN and allows for multiple numbers, groups, queues, hold music and more. It generally takes up a much smaller part of the market these days as other kinds of broadband connection have taken over, meaning there is less need for it.

VoIP or Voice over Internet Protocol is an increasingly popular form of business communication. All your calls are taken over your internet connection and many more simultaneous features are available.

There’s no need for a physical exchange on the premises to receive and distribute calls because it’s all done online. We’ll talk a little bit more about the main features below.


There’s a big change coming. The traditional analogue forms of communication that many businesses still use, are officially outdated.

The maintenance costs of keeping these lines, with their copper wires, up and running is increasing and BT are moving on. From December 2023 you will not be able to buy and install PSTN or ISDN and in December 2025 the lines will be shut off completely rendering them unusable.


You may be thinking that these dates are a long way in the future, do we really need to worry about it now?

And you’re right there is a while to go. However, in some cases the support for these systems will cease earlier and you don’t want to be put in a spot of bother when it comes to communication.

Even then, there’s a better reason for thinking about it which is, why wait?

Many businesses are already moving over to the cloud in a number of different ways and although it can seem daunting at first, it’s actually relatively straightforward.

There are also many benefits to VoIP that will streamline your business and get you ahead of the competition.



It used to be that the cost of ISDN was wrapped up in your line rental and broadband package. The provider would charge businesses an overall fee for usage which wouldn’t necessarily have been the cheapest option.

VoIP providers generally charge per person and individual calls are cheaper because they’re not using the same old tech. This means they can deliver a scalable, manageable, monthly subscription. It suits your business whatever the size.

There are also no maintenance costs and often no set up fees. It’s all included in the monthly cost.


You can access VoIP on your mobile, tablet and desktop, wherever you are and your business number goes with you.

This is particularly important if you have a remote workforce, an experience many will have had this year.

In the same way if the business ever moves premises, they can simply take the number with them. It all exists on the cloud. No need to faff around transferring numbers.


Cloud-hosted telephony means you can have as many features as you like. You aren’t limited by the hardware you install.

Features which include call recording, email voicemail and unified comms (integrate it with Microsoft Teams) all make for a well-rounded system that means your office communication is completely streamlined.

Not only this but you can also get detailed analytical data and implement controls which can actually help to drive your business forward. The call data can combine with your CRM and customer data to make for a more effective sales strategy.


Are you ready to join the thousands of other businesses moving over to VoIP? There’s still time of course but with so many benefits available why wait for the time when you have no choice.

The switch off will soon creep up on us so you certainly don’t want to be caught out.

The good news is that we can deliver a trusted and effective cloud hosted VoIP system for your business!

At Reality Solutions, we have collaborated with 3CX so we can provide you with a modern a modern VoIP telephone system which is packed full of advanced features to benefit your business whether you are working on-site or away from the office.

3CX is an ideal replacement to outdated traditional telephone systems and is a perfect choice for any business of any size at an affordable price.

Some of the benefits of 3CX include,

  • Easy Installation & Management – Pre-configured templates for easy integration with leading SIP Trunk providers
  • High Quality Calls – High quality codecs ensure your calls always sound great
  • Save on Telco Costs – Save on call costs by lowering mobile & customer service number bills
  • Connected Anywhere – Use your office extension anywhere with the 3CX mobile apps and web client
  • Safe & Secure – 3CX proactively protects you against security threats in real-time.
  • Flexibility – Seamlessly switch between handset, headset and or mobile device
  • Head in the Clouds – 3CX can be installed on a physical or virtual server on-premises or deployed to the cloud

To find out more information about 3CX, please contact our Sales Team on 03300 160565.

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