A guide to the impact of the PSTN switchover: from EPOS to alarms and everything in between

Table of contents

What, when and why?

What within my business is going to be affected?

Will it require a lot of work and cost to change?

Get ahead of the switch off

With the PSTN/ISDN switch off fast approaching (scheduled for 2025), many businesses are wondering how this event will change the infrastructure of their enterprise and what can be done to negate any potential disruptions to business as usual. That’s why we’ve created this impact guide explaining what hardware will be affected and how it can be upgraded without any unnecessary costs to your organisation.

Letting go of the analogue system and upgrading to a fully digital service that uses internet protocol (IP) may seem complex at first glance, but switching your EPOS, alarms, telephones (and more) to hardware that runs across a fibre-based network (such as VoIP and SIP trunking systems) can be made simple and easy.

What, when and why?

The PSTN (Public Switched Telephone Network) and ISDN (Integrated Services Digital Network) are two different networks that work in tandem to transfer voice, video and other data over the UK’s phone lines. Due to the high cost of maintenance and rapidly expanding digital activity in the UK, BT announced that they would be switching off the networks in December 2025 and transferring all communications infrastructure to a faster and more efficient fibre-based system.

This new system will use the internet to transfer data and has been an ongoing process since 2020. For businesses, this means that any hardware (like phones, alarms, CCTV, security alarms) that run on the old technology (or are not compatible) will no longer function after the switch off.

What within my business is going to be affected?

Below is a list of the core hardware of your communications infrastructure that will be affected by the networks being turned off:

Business phone lines: The ISDN was originally created for businesses because of the limitations of the PSTN. Many businesses use ISDN lines (whether they are ISDN2, ISDN30 or Wholesale Line Rental) to run their telephone services, so the ISDN switch off will mean that any telephone hardware running on the ISDN will cease to function.

Home phone lines: A PSTN line, more commonly known as a home phone line or landline, is directly connected to the PSTN. As the PSTN will be switched off at the end of December 2025, along with all other fixed lines and certain broadband services, old home phone lines will be retired.

Security alarms: Older signalling systems use a digital communicator that is connected directly to your phone line and, therefore, the PSTN or ISDN. After the switchover, these communicators (and the alarm systems) will no longer work.

CCTV: Many closed-circuit television surveillance systems send a signal across the PSTN when suspicious activity is detected. Once the PSTN has been decommissioned, these CCTV systems will no longer be able to send this alert to business owners, rendering them defunct.

EPOS machines: For many small businesses, EPOS (Electronic Point of Sale) systems (and the card machines that use them to fulfil financial transactions) are often connected to their phone line. With the switching off of the PSTN and ISDN, your old EPOS system will not be able to connect to your card machines.

Fax machines: Fax (short for facsimile) machines usually access the PSTN via an analogue interface in order to send fax information. When the PSTN is shut down, incompatible fax machines will no longer be able to send data.

Premises entry/exit systems: Many security access door panels are connected to the PSTN via your telephone line. These systems can be easily switched to operate wirelessly, but any component using the PSTN will become inactive after the networks are switched off.

As you can see, many systems integral to the functioning of a business are still connected to the PSTN or ISDN. That’s why, when you contact Focus Group about the switchover, we can ensure that all of these areas are addressed together.

Will it require a lot of work and cost to change?

As a compulsory change that all UK businesses need to make before 2025, the impact of not switching over to IP technologies could be extremely costly and time consuming. However, the process of upgrading your infrastructure can be simple and efficient and will present a number of benefits for your enterprise moving forward.

The shift to fibre-based infrastructure and IP technology will provide better speeds and quality, which will aid businesses in their expansion and productivity goals. Fully digital services, like VoIP technologies, mean little or no cost for phone calls and a much more flexible service. Even if your business has to pay an early termination fee for their current ISDN contract, you could see savings of up to 50-70% on the cost of calls (with no monthly line rental and very low ongoing maintenance costs) when you upgrade.

Get ahead of the switch off

With the 2025 deadline approaching fast, we recommend getting prepared for life after ISDN and PSTN sooner rather than later, so you can get a jump on the competition and benefit from better connectivity at a lower cost. Our team of infrastructure experts at Focus Group can help make the process quick, smooth and stress-free. We’ll handle every aspect of your IP upgrade (including the installation and monitoring of all your new devices), leaving you to get back to the more important things, like growing your business.