PSTN Switch-Off 2025 — Is Your South Wales Business Ready?

What is the PSTN switch-off?

PSTN stands for Public Switched Telephone Network — the traditional copper wire phone network that has been the backbone of UK communications since the 1800s. BT Openreach has announced it will permanently decommission both the PSTN and ISDN (Integrated Services Digital Network) by December 2025.

This affects every business in the UK that still uses a traditional analogue landline, ISDN2, ISDN30, or a phone system connected to the old copper network.

Who does this affect?

If your business has any of the following, you are affected:

• A traditional BT landline
• An ISDN2 or ISDN30 connection
• An on-premise PBX phone system connected to the analogue network
• A broadband connection delivered over copper (ADSL/FTTC "fibre" that uses a copper last mile)
• Payment terminals, door entry systems, lifts or alarms that use analogue lines

What happens if you do nothing?

When the switch-off happens, your analogue phone lines will simply stop working. No warning, no grace period — they'll go dead. Your business will be unable to make or receive calls, potentially losing inbound sales, customer service capability and emergency communications overnight.

Beyond phones, any systems that rely on analogue connections — door entry, CCTV, payment terminals, panic alarms, fire systems and lift emergency phones — may also stop working if they use analogue lines as their communication path.

What's the solution?

The replacement for PSTN is VoIP (Voice over Internet Protocol) — phone calls made over your broadband connection rather than copper wires. Modern VoIP systems are more reliable, more flexible, and often significantly cheaper than traditional landlines.

There are several options depending on your business size and requirements:

1. Hosted VoIP / Cloud Phone System

Your phone system lives in the cloud. Engineers at Thorne Technology configure your desk phones (or softphones on computers/mobiles) and your calls run over your internet connection. No on-site hardware required. This is the right solution for most South Wales SMEs.

2. SIP Trunks

If you already have a modern on-premise PBX, SIP trunks replace your ISDN lines with internet-based equivalents — often at a fraction of the cost. Your existing handsets and system stay in place.

3. Microsoft Teams Calling

If your business already uses Microsoft 365, Teams Direct Routing lets you make and receive external calls directly through Teams. No separate phone system needed at all.

What about broadband?

Many businesses in South Wales still receive their broadband over FTTC (Fibre to the Cabinet) — which uses fibre to the street cabinet, then copper to the building. This will also be affected. Openreach's SOGEA product provides a broadband-only service over copper without the voice line, while full fibre (FTTP) replaces the copper entirely.

We recommend using the switch-off as an opportunity to upgrade to full fibre if it's available in your area — speeds, reliability and latency are all dramatically better.

How Thorne Technology can help

We've been helping South Wales businesses migrate away from legacy phone systems for years. Here's what we offer:

• Free audit — we'll assess every analogue connection in your business
• VoIP migration — full project management, number porting, system configuration
• Eve UC deployment — our preferred hosted telephony platform for South Wales businesses
• Microsoft Teams calling — Direct Routing setup for Microsoft 365 customers
• SIP trunks — if you want to keep your existing PBX
• Ancillary systems check — we'll identify every alarm, lift, door entry or terminal using an analogue line

Summary

• PSTN and ISDN switch off December 2025 — this is confirmed and non-negotiable
• Any business on analogue lines or ISDN will lose phone service unless they migrate
• VoIP is the replacement — more flexible, often cheaper, works over your existing broadband
• Don't forget non-phone analogue lines: alarms, lifts, payment terminals, door entry
• Act now — migration backlogs are growing as the deadline approaches