PSTN Switch Off Checklist for UK Businesses

The PSTN has been the backbone of UK telephony for decades, but it’s outdated, expensive to maintain, and simply not built for the digital world we now live in. The replacement, IP Telephony, is faster, more flexible, and far more future proof.

Here’s the important bit- if your business still relies on anything that plugs into a traditional phone line, you’ll need to migrate it. “Anything” covers more than you might think. 

Many companies assume that the switch off only impacts desk phones, but the PSTN supports far more.

Check if your organisation uses:

·       ISDN phone systems

·       Analogue landlines

·       Fax machines

·       Alarm systems (fire, intruder, lift alarms)

·       Door entry systems

·       Lift emergency phones

·       EPOS payment terminals (older PDQs)

·       CCTV Connectivity

·       Telecare Devices

·       Legacy broadband services (ADSL/FTTC)

·       Telemetry or Monitoring Equipment

If it uses a copper line, it’s affected.

This is the step that many businesses underestimate. It’s not just about phones. If you rely on any of these services, you are likely affected (unless they are already migrated to IP).

One of the biggest risks that businesses face is hidden PSTN dependencies. Many organisations discover critical devices only when they fail during migration. If you leave migration to the last minute this could present even more problems.

Create an inventory including:

·       Phone numbers

·       Hardware models

·       Lines and circuits

·       Connected services

·       Site locations

·       Suppliers

Once you know what you have, rank items by business impact.

·       High priority: customer-facing phone lines, alarms, payment systems.

·       Medium priority: internal phones, door entry systems.

·       Low priority: fax machines, legacy equipment you may retire anyway.

This helps you to budget and create realistic timelines.

You also need to check the compatibility of non-voice devices. Some devices may not work reliably over IP without upgrades. Contact your suppliers for these systems and ask:

·       Is this device suitable with all IP networks?

·       Do you offer an IP-ready version?

·       What is the recommended migration path?

Don’t assume that it will probably work, test everything.

Check:

·       Telecoms contract end dates

·       Maintenance agreements

·       ISDN line rental terms

·       Early termination penalties

You may be able to align migration timing with contract renewals to reduce costs.

All IP services rely on a stable internet connection. If you are still on ADSL or FTTC you will need to upgrade anyway ahead of the switch off.

Options include:

·       Full Fibre (FTTP)

·       SOGEA- Fibre-based broadband without a phone line

·       Leased lines- dedicated, guaranteed bandwidth for larger sites

A modern low latency connection with sufficient bandwidth ensures your new digital services run smoothly.

For many organisations, this transition becomes an opportunity to modernise communications, not just replace them. However, if you would like to keep your systems as close to they are now as possible, there are often ways of doing so (as long as your devices supports IP).

Most businesses decide to move to VoIP (Voice over Internet Protocol) or cloud-hosted phone systems.

When deciding on the best approach for your business you should consider:

·       Remote and hybrid working needs

·       Multi-site connectivity

·       Integration with CRM or Microsoft Teams

·       Call reporting and analytics

·       Scalability for growth.

You may decide to opt for:

·       VoIP Handsets

·       Softphones (apps on mobiles and laptops)

·       Hosted PBX Systems

·       SIP Trunks and Lines to keep your existing on-premise phone system but make it digital.

During the migration process, it is important that downtime is minimised as much as possible to prevent disruption to customer experience.

You should plan:

·       Migration timelines

·       Temporary call routing

·       Backup internet connectivity

·       Failover phone options

Moving forwards, your business is going to be more reliant on the Internet. If your Internet drops, your business shouldn’t. There is further planning that needs to take place to account for this.

Power resilience should also be considered. Traditional analogue phones often worked during power cuts. Digital systems usually don’t, unless they are specifically designed to. This is where the importance of mobile failover options and emergency calling procedures comes into play. This is particularly important for healthcare, hospitality and public-facing organisations. Here at CloudConnX, we have this in our solution set and have assisted many organisations to deploy battery backup systems for such events where power is lost.

Digital telephony introduces new security considerations. You will need to review network security policies, call encryption, access controls and compliance requirements (GDPR, PCI-DSS if relevant).

A properly designed system is typically more secure than legacy PSTN services, but only if configured correctly.

Don’t wait until the final months of 2026. Suppliers will be overwhelmed, lead times will stretch, and cost and risk will increase.

Aim to have completed your migration with breathing room for testing, training, and troubleshooting.

Once the deadline is here, phone numbers that haven’t been migrated will be lost forever.

As you may have realised, migrating to digital ahead of the switch off involves far more than simply replacing phone lines for the majority of businesses. A professional provider ensures that multi-site networks, legacy systems, and connected devices like alarms, EPOS, and security systems continue to function without disruption, minimising downtime and business risk. Working with a migration partner means that they can apply their expertise and experience to ensure the move to digital goes smoothly. Attempting to work through the migration alone can lead to costly mistakes, service interruptions, and overlooked dependencies.

• Assuming ‘we have plenty of time’
• Forgetting ‘non-phone’ devices
• Underestimating connectivity requirements
• Choosing the cheapest option instead of the right one
• Not planning resilience or failover

Whilst the PSTN Switch Off can seem like a big disruption, it’s also a chance to:

• Improve flexibility for hybrid working
• Reduce telecom costs
• Increase reliability
• Add advanced features
• Integration communications systems with other internal systems
• Future-proof your infrastructure
• Keep your number when relocating – once migrated to IP-based telephony, your business phone numbers are no longer tied to a physical location, making office moves seamless.

Many of the organisations we have already migrated to digital have made cost savings resulting from the identification of legacy lines that were not being used but still being paid for.

If you’re unsure whether your organisation is fully prepared for the PSTN switch-off, the safest approach is to start with a professional assessment. Here at CloudConnX, we have already helped businesses from a variety of sectors make the transition to Switch Off-ready infrastructure.

We help businesses like yours avoid costly errors, minimise downtime, and turn the PSTN switch-off into an opportunity to modernise communications and improve operational efficiency.

Our team of experts has decades of experience working in the communications industry, enabling them to tailor a migration plan to meet the specific needs of your business. There are no one-size-fits-all solutions here, as we recognise that the needs of each business are individual.

Start the conversation with us today, and let’s explore your unique requirements so we can create a plan that ensures a smooth, future-proof transition.

Reach out on 0330 122 0550 or email This email address is being protected from spambots. You need JavaScript enabled to view it.