7 Services You Didn’t Know Still Use PSTN – And What to Do About It

The UK’s PSTN and ISDN networks are being switched off by January 2027, yet thousands of businesses remain unaware of just how deeply embedded these legacy systems are in their daily operations.

You might have migrated your phone lines already—but what about your alarms, access control, or card machines?

In this blog, we reveal seven commonly overlooked services that still depend on the analogue Public Switched Telephone Network (PSTN) and explain what to do next.

Why the PSTN Switch-Off Matters

The PSTN switch-off isn’t just about telephony. It’s about retiring all copper-based infrastructure—including devices and services that were installed years ago and never upgraded.

Since September 2023, Openreach has stopped selling new PSTN/ISDN services. By the end of January 2027, the network will be completely shut down.

If any part of your business still depends on this infrastructure, you could face:

• Service outages
• Compliance risks
• Emergency systems failure
• Unexpected costs

7 Services Still Using PSTN You Might Have Missed

1. Lift Emergency Phones

Many buildings, especially older commercial or residential blocks, use PSTN lines for lift emergency call systems. These systems are easy to overlook but are often compliance-critical.

What to do: Upgrade to GSM, VoIP, or IP-based auto-diallers, and ensure compliance with BS EN81-28 standards.

2. Security & Fire Alarms

Intruder alarms, fire panels, and monitoring systems frequently use PSTN for signalling. These connections are typically installed once and forgotten—until they stop working.

What to do: Engage your alarm provider to check if your signalling path needs to be upgraded to digital/IP-based systems.

3. Door Entry & Access Control Systems

Remote intercoms and entry systems often rely on PSTN to route calls to desk phones or mobile numbers. Many of these are still analogue and will fail when the network goes offline.

What to do: Migrate to IP-enabled door entry systems or GSM-based alternatives.

4. Card Payment Terminals (PDQ Machines)

Some older point-of-sale (POS) or backup card readers still use dial-up connections over PSTN. This is especially common in rural locations or pop-up stores.

What to do: Ensure all payment terminals are updated to IP or 4G-enabled models.

5. Fax Machines & Multi-Function Printers

Still surprisingly common in sectors like legal, healthcare and local government, fax machines are entirely dependent on analogue lines.

What to do: Move to secure e-fax or document sharing platforms. Many MFPs now offer direct cloud-to-email fax functionality.

6. Retail EPOS Systems

Legacy tills, particularly in smaller shops or franchises, may use PSTN connections for payment verification or failover routing.

What to do: Review all POS infrastructure and speak to your vendor about broadband or mobile-based connectivity.

7. Monitoring, Metering & BMS Devices

Older building management systems (BMS), HVAC monitors and utility meters may still dial out via PSTN for remote monitoring.

What to do: Audit these devices and plan a migration to IP-enabled or IoT-connected alternatives.

How to Find Out What’s Still at Risk

If your business hasn’t completed a full PSTN audit, you may be unaware of how many systems are still dependent.

Common signs include:

• Devices connected via standard phone sockets
• Lift or alarm systems installed more than 5 years ago
• DSL broadband lines (ADSL or FTTC)

Not sure where to start? Book a PSTN impact audit with Misco.

What Should Replace PSTN?

Depending on your business size and infrastructure, your PSTN-dependent services can be replaced with:

Ready to Future-Proof Your Communications?

Misco is here to guide your business through a seamless transition from analogue to digital.

What’s included in our free PSTN switch-off audit:

• Full infrastructure review
• Identification of hidden PSTN dependencies
• Personalised migration roadmap
• Cost and downtime mitigation planning

Or call us directly on 0800 368 9646