Southampton Businesses: Preparing for the PSTN Switch-Off (2025) – What You Need to Know

Big changes are coming to the way UK businesses make phone calls. By December 2025, the Public Switched Telephone Network (PSTN) and Integrated Services Digital Network (ISDN) will be switched off nationwide.

This PSTN switch off UK plan will affect countless Southampton companies that rely on traditional phone lines, analogue phone lines, and older telephone networks.

For local businesses, this switch off isn’t just about changing technology. It’s about ensuring reliable communications, avoiding service interruptions, and keeping business customers happy.

If you’re still using PSTN lines or ISDN services, now is the time to act.

What Is the PSTN and Why Is It Being Switched Off?

The switched telephone network (PSTN) is the legacy telephone exchange system that's been in use for decades across the UK. It uses analogue lines to carry voice signals over copper cables.

The Integrated Services Digital Network (ISDN) was introduced to bring digital transmission to the PSTN, allowing for both voice services and data.

But these systems are old. The PSTN network is expensive to maintain, and it's increasingly incompatible with modern digital technology.

By 2025, the UK is moving to a fully digital network. That means phasing out traditional pstn lines, analogue phone lines, and ISDN services in favour of IP-based communication systems like VoIP (Voice over Internet Protocol).

When Is the PSTN Switch-Off Happening?

BT has confirmed the PSTN switch off date is December 2025.

Between now and then, phone companies and telecoms companies are phasing out PSTN services and ISDN lines for new customers.

This "big PSTN switch off" is happening everywhere, from city centres to suburbs, including Southampton.

What Will the PSTN Switch-Off Affect?

The switch off will impact more than just phone lines. It affects vital services that many businesses rely on:

✅ Analogue phone lines and traditional phone services

✅ ISDN and services digital network ISDN lines

✅ Fax machines

✅ Alarm systems and door entry systems

✅ Payment terminals relying on analogue lines

✅ Older broadband services using PSTN lines

If your business uses existing services built on the switched telephone network, you'll need to plan a digital solution.

Why Is the UK Moving to Digital Voice Services?

This isn't just about shutting old tech down. It's about delivering reliable communications, better voice quality, and modern digital voice services.

A fully digital service offers:

✔ Cheaper or even unlimited calls, including international calls

✔ Call forwarding, instant messaging, video conferencing

✔ Integration with customer relationship management systems

✔ Better support for mobile and internet communications

✔ Seamless use across mobile phone, desk phone, and apps

Put simply, the move to digital voice makes business communications fit for the future.

How VoIP Services Are the Answer

The main digital alternative to PSTN is VoIP technology (Voice over Internet Protocol).

VoIP services deliver voice calls over your internet connection, rather than analogue lines.

Benefits of VoIP phone systems include:

✅ Lower costs, even for business calls and international calls

✅ Work anywhere with internet connectivity, perfect for hybrid and remote work

✅ IP-based communication systems allow voice, video, and data to converge

✅ Flexible use on mobile phone network, mobile devices, desk phones, and computers

✅ Advanced voice services with call forwarding, voicemail greetings, and more

It's the digital voice service designed for UK businesses in 2025 and beyond.

Do Southampton Businesses Need to Worry?

If you're in Southampton (or anywhere in the UK), you can't ignore the PSTN switch.

Existing services using analogue lines or ISDN will simply stop working after 2025.

That means no phone calls, fax machines, or alarm systems that depend on the switched telephone network. Even broadband connection might be affected if you're still on older PSTN services.

For business customers, that could mean:

❌ Missed emergency calls

❌ Lost business calls

❌ Frustrated customers and damaged customer satisfaction

❌ Disruption to vital services

How Should Southampton Businesses Prepare?

Here’s a step-by-step approach:

1️⃣ Audit Your Current Phone System

• Are you still using analogue phone lines or ISDN services?

• What devices depend on them (fax machines, alarm systems, door entry systems)?

• Identify all existing services tied to PSTN lines.

2️⃣ Review Your Internet Connection

VoIP and other digital solutions need strong internet connectivity.

• Check your broadband services and broadband connection quality.

• Consider fibre broadband if available.

• Ensure reliable communications even at peak time.

3️⃣ Choose Your Digital Alternative

• Select a VoIP provider or communication provider.

• Look for VoIP services with advanced features like call forwarding, instant messaging, and video calling.

• Ensure compatibility with mobile and internet communications.

4️⃣ Plan Your Migration

• Set an installation date well before 2025.

• Test voice services to ensure uninterrupted access.

• Train staff on new digital phone lines and features.

5️⃣ Think About Compliance

• Ensure your solution can handle emergency services access.

• Discuss battery back up unit options for power cuts.

• Make sure vulnerable customers can still receive calls.

What About Broadband Services?

Your internet connection is critical. VoIP services depend on strong, reliable broadband.

Consider:

✅ Upgrading to faster broadband services

✅ Checking your broadband connection with a postcode checker

✅ Talking to your communication provider about future proof plans

A solid internet protocol backbone ensures smooth voice calls and video conferencing, plus support for mobile devices and digital services.

How IT Support Southampton Can Help

We’re local experts who understand Southampton businesses.

We can:

✅ Audit your existing services and equipment

✅ Recommend the right digital solution or VoIP services

✅ Help upgrade your broadband connection

✅ Install and configure your new IP-based communication system

✅ Offer software support and protect against software vulnerabilities

✅ Provide financial support options and guidance if available

We know the PSTN switch off UK is a big change. But we’re here to make it smooth, affordable, and tailored to your needs.

Don’t Wait Until the Last Minute

The PSTN switch off is coming whether we’re ready or not.

By planning now, you can:

✔ Avoid losing voice services

✔ Ensure emergency services access

✔ Keep business customers happy

✔ Upgrade to fully digital network technology

✔ Future-proof your business communications

Ready to Get Started?

If you’re in Southampton, don’t leave your business connected to outdated PSTN network technology.

📞 Contact IT Support Southampton today. Let’s plan your transition to a modern, reliable, digital voice service that supports all your voice calls, internet communications, and business operations, now and into the future.