Navigating the PSTN switch-off: steps businesses must take to stay prepared

With one year to go, preparing for the public switched telephone network (PSTN) switch-off should be a top priority for every small and medium-sized business in the UK. Here, Kristian Torode, Director and Co-Founder of business communication and PSTN switch off specialist Crystaline, offers a complete checklist of everything your business needs to review as we ring in the new year.

For decades, the PSTN has been the backbone of business communications in the UK. But that era is coming to an end. BT has confirmed that the official switch-off will take place in early 2027 and the countdown has begun. Despite years of warnings and extended planning windows, BT and Frontier Economics report that “UK customers still make roughly 40 billion minutes of fixed-line calls annually.”

The PSTN no longer meets the demands of modern, digital-first businesses. Its limitations go beyond inconvenience: companies risk communication blackouts, failed payments, alarm system breakdowns, and serious reputational damage. For many SMEs, these risks directly impact revenue, customer trust, and day-to-day operations, making preparation this year essential. So, what should SMEs do this year to get ready?

1. Audit everything

Start with a thorough audit of all PSTN-dependent systems. Remember, the PSTN powers more than just telephones: it can also be linked to alarm systems, card payment terminals, door entry systems, and even metering equipment.

Involve facilities, finance, and operations teams to identify every dependency. Document how your telephone answering and support systems currently work so that the experience for callers remains seamless during and after the transition. This step is especially critical for customer-facing businesses, where even short periods of downtime can lead to lost sales and frustrated customers.

2. Check your internet connection

Once the PSTN is switched off, all calls will rely on your internet connection. Ensure your current broadband is reliable and strong enough to handle the increased demands of a digital phone system.

If you’re still using copper-based services such as ADSL, it’s time to upgrade to fibre. A robust, resilient connection protects call quality, helping avoid dropped calls, delays, and frustrated customers. Think of your internet as the foundation of your communications strategy: without a solid base, everything else could collapse.

Businesses should also consider resilience at this stage. Secondary internet connections or automatic call failover to mobiles can ensure critical calls still get through if your primary connection fails. For many SMEs, this level of continuity planning is the difference between a minor disruption and a serious operational issue.

3. Review hardware

Assess whether your desk phones, headsets, and routers are VoIP-ready. Some older devices may need adapters, while others may require full replacement.

This is also a chance to streamline your setup. Remove unused or duplicate lines and equipment. Simplifying now will save time, reduce costs, and make your new system easier to manage. A leaner setup also makes future upgrades faster and less disruptive.

4. Choosing the right phone system

Selecting the right phone system is critical for a successful transition. While some businesses can adapt their legacy PBX systems using SIP trunking, the most future-proof solution is a cloud-based Unified Communications (UC) platform.

These systems offer much more than voice calls, integrating video conferencing, messaging, file sharing, and analytics in a single, user-friendly platform. One example is Vodafone Business UC with RingCentral, available through Crystaline. This solution combines Vodafone’s reliable network with RingCentral’s advanced Cloud technology, delivering voice, video, messaging, and collaboration in one secure, scalable system – ideal for hybrid teams and multi-site operations.

For growing SMEs, cloud UC platforms also reduce reliance on on-site hardware, lower maintenance costs and make it easier to scale up or down as business needs change.

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5. Train your team

Technology is only as effective as the people using it. Focus training on teams that rely most on phones, including customer service, sales, reception, and operations.

Their feedback will reveal any issues before the system goes live. Training should not only cover how to use the new system, but also how to leverage new features to improve customer experience. Well-prepared teams help ensure customers notice improvements, not disruption, during the transition.

6. Set a clear timeline and test for continuity

Establish a timeline that includes testing, training, and a phased rollout. The PSTN switch-off is scheduled for 31 January 2027, leaving no room for delay. Treat this transition as a major business transformation and plan accordingly.

Testing should include real-world scenarios, such as internet outages, peak call volumes, and remote working conditions, to ensure critical services like payments, alarms and customer support remain operational. Leaving this too late risks rushed decisions, supplier bottlenecks, and avoidable downtime.

Although moving away from PSTN is mandatory, it’s also an opportunity. Modern communication systems can deliver better customer experiences, smarter analytics and greater flexibility for teams. Audit your systems, upgrade where needed, train staff and test thoroughly to ensure your business stays connected and competitive in a fully digital environment.