As of 1 January 2026, small and medium-sized businesses across the UK should have had one priority firmly at the top of their agenda: preparing for the PSTN switch-off

CREDIT: This is an edited version of an article that originally appeared in SME Today

For decades, the Public Switched Telephone Network (PSTN) has underpinned business communications. But in a digital-first world, it is no longer fit for purpose. Its limited capabilities cannot support modern business needs, and failing to prepare for its retirement could lead to more than minor disruption.

BT has confirmed the official switch-off will take place in early 2027, and the clock is now ticking. Despite long-standing warnings and extended preparation windows, BT and Frontier Economics report that customers still make around 40 billion minutes of fixed voice calls in the UK every year. If you haven’t yet begun preparing, now is the time to review what needs to be done, checked and planned.

Step One: Audit Your PSTN Dependencies

The first step is a thorough audit of everything in your organisation that relies on the PSTN. While phones are the most obvious example, many people overlook other critical systems connected to legacy lines. These may include alarm systems, door entry controls, card payment terminals and metering equipment. This process should involve facilities, finance and operations teams to ensure nothing is missed. It’s also important to document how calls are currently routed and handled.

Step Two: Strengthen Your Internet Connection

Once PSTN services are switched off, all voice calls will be delivered over the internet. That makes your broadband connection the foundation of your future communications strategy.

Organisations still using copper-based broadband such as ADSL should prioritise upgrading to a fibre-based service. A fast, reliable and resilient internet connection will protect call quality and ensure your systems can cope with increased demand once digital telephony is in place.

Step Three: Review and Update Your Hardware

Next, assess your existing hardware. Desk phones, headsets and routers all need to be compatible with Voice over Internet Protocol (VoIP). Some older devices may work with adapters, while others will need replacing altogether. This is also an opportunity to simplify. Removing unused lines and redundant equipment can reduce costs, cut complexity and make your new system easier to manage in the long term.

Step Four: Set a Clear Transition Timeline

The final piece of the puzzle is planning. Create a clear timeline that includes testing, staff training and a phased rollout. This allows teams time to adjust and iron out any issues well before the deadline. With a hard cut-off date of 31 January 2027, when the PSTN will be fully switched off, there is no flexibility. This is a significant operational change and should be treated as an organisational transformation, not a last-minute technical fix.

Looking Ahead

The big switch off is coming, and those that act now will be best placed to manage it with confidence. By auditing systems early, upgrading connectivity, modernising hardware and planning carefully, organisations can avoid any nasty surprises, ensure a smooth transition and keep things ticking over – both during the changeover and long after the PSTN is gone.