The unexpected impact of the PSTN switch-off: from business phones to emergency alarms

Table of contents

What, when and why?

How is my business going to be affected?

Will it cost me a lot of time and money to change?

Get ahead of the switch-off

With the PSTN/ISDN switch off fast approaching (scheduled for 2027), 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. Take a look through our page on switching to VoIP to see just how easy the process can be.

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 2027 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.

How is my business going to be affected?

The transition away from PSTN and ISDN networks will impact several core components of your communications infrastructure. Here’s a detailed look at what will be affected:

Business phone lines: Originally developed to overcome the limitations of PSTN, ISDN lines (including ISDN2, ISDN30, and Wholesale Line Rental) are widely used by businesses for their telephone services. With the ISDN switch off, any telephone hardware dependent on ISDN will cease to function. This necessitates an upgrade to VoIP or SIP Trunking systems to maintain business continuity.

Home phone lines: Commonly referred to as landlines, home phone lines are directly connected to the PSTN. As of the end of January 2027, the PSTN and all associated fixed lines will be decommissioned. Consequently, traditional home phone lines will be retired, requiring users to switch to modern alternatives like VoIP.

Security alarms: Older security alarm systems often use digital communicators that rely on PSTN or ISDN connections. Post-switchover, these communicators—and the alarm systems they support—will no longer be operational. Upgrading to modern alarm systems that use IP-based communications or cellular networks is essential to ensure continued security.

CCTV systems: Many CCTV systems send alerts over the PSTN when detecting suspicious activity. The decommissioning of the PSTN will render these systems unable to send alerts, making them ineffective. Upgrading to internet-based or cellular CCTV systems will be necessary to maintain surveillance capabilities.

EPOS machines: EPOS systems, including the card machines that facilitate financial transactions, often connect via phone lines. With the discontinuation of PSTN and ISDN, these systems will lose their connectivity. Transitioning to internet-based EPOS solutions will be crucial for uninterrupted business operations.

Fax machines: Fax machines typically use an analog interface to connect to the PSTN for sending documents. Once the PSTN is shut down, these machines will be unable to transmit data. Businesses will need to adopt online fax services or upgrade to modern fax machines compatible with digital communication methods.

Premises entry/exit systems: Many security access door panels are connected to the PSTN through telephone lines. After the network switch off, these systems will become inactive unless they are adapted to operate wirelessly or through IP-based connections. Ensuring these systems are upgraded will be vital for maintaining secure access control.

In summary, the switch-off of PSTN and ISDN networks will significantly impact various communication and security systems within your business. Proactively upgrading to modern, internet-based solutions will not only ensure your operations remain uninterrupted and future-proof, but will actually be safer for people who use the old PSTN systems.

Will it cost me a lot of time and money to change?

As a compulsory change that all UK businesses need to make before 2027, 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 2027 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.