What does the PSTN switch-off mean for my phone line?

If you've had a letter about the "big switch-off", or you're worried about an elderly relative's landline, take a breath. Nobody's phone is being cut off without warning. The PSTN switch-off is a planned, nationwide change to how landlines work, and providers are moving customers across in stages, contacting each household before anything happens. This guide explains, in plain English, what the switch-off actually is, what happens to your phone line, why your broadband may have to move at the same time, and what (if anything) you need to do right now.

The PSTN switch-off means your old landline moves to digital voice, and if your current broadband depends on that analogue phone line, the broadband has to move too. On a typical FTTC line with a landline, porting the number usually ceases the old line, so the broadband must be migrated to SOGEA or upgraded to full fibre.

What is the PSTN switch-off, and when does it affect my landline?

PSTN stands for the Public Switched Telephone Network: the analogue phone system that has carried UK landline calls for well over a century. It's the copper-line technology behind the traditional phone plugged into the wall socket. The network is old, expensive to maintain, and being retired across the whole country. The national deadline for the switch-off is 31st January 2027. You can read a short definition of the term on our PSTN switch-off glossary entry.

What's important to understand is that the switch-off is the national backdrop, not the exact moment your own phone changes. In practice, the change happens to your line when your provider migrates you, which is usually some time before that deadline. They contact you first, explain the move, and arrange it. Nobody's landline simply goes dead on the morning of the deadline with no notice.

The headline is reassuring: your phone number stays the same, you keep a working home phone if you want one, and the change is managed for you. The detail worth knowing, and the part most articles get wrong, is what happens underneath, especially if your broadband currently rides on that same phone line. We'll come to that.

What happens to my phone line when it moves to digital voice?

When the analogue line is retired, your phone service moves to digital voice, sometimes called VoIP (Voice over Internet Protocol). Instead of travelling down a dedicated copper phone line, your calls travel over your broadband connection. Inspire's digital voice product is LightLine, and the experience for everyday use is much the same as before: you pick up a handset, dial a number, and make a call.

For most people, the practical difference is small. You keep your landline number. Call quality is usually as good or better. The main change is how your phone connects: instead of plugging into the old wall phone socket, a digital voice handset typically plugs into the back of your router, or connects over your home wifi. Your provider will tell you exactly how your setup works when they arrange the move.

There's one genuinely important difference to flag early, and we cover it in full further down: a digital voice phone relies on power and broadband, so it doesn't work in a power cut the way an old analogue phone did. That matters most for anyone who depends on the phone in an emergency, or who has a care alarm. Hold that thought.

What happens to my broadband if I still have FTTC and a landline?

This is the part that trips people up, so it's worth being precise. A lot of UK homes are on FTTC (fibre to the cabinet), where fibre runs to the green street cabinet and the final stretch into your home is copper. On many of these setups, the broadband is delivered on top of the old analogue phone line, an arrangement the industry calls WLR (Wholesale Line Rental). In plain terms: your broadband and your landline share the same underlying copper line.

Here's the mechanism that catches people out. When your phone number is ported to a digital voice service, that old WLR phone line is ceased automatically. And if your FTTC broadband was riding on that line, it cannot continue: it drops when the line is ceased. So a typical WLR-plus-FTTC household can't simply move the phone to digital and leave the broadband exactly as it was. The broadband has to move at the same time. You can read a plain definition on our FTTC glossary entry.

That leaves two clean options for the broadband. The first is standalone broadband on the same cabinet network, without the old phone line attached: standalone broadband on the old cabinet network is often called SOGEA. It uses the same cabinet and the same copper into your home as FTTC, but it stands on its own, with no WLR phone line underneath. The second option is to upgrade to FTTP (fibre to the premises), full fibre all the way to the house. Our full fibre vs FTTC guide walks through the difference between these in more depth, and you can also read the SOGEA glossary entry for the short version.

None of this is something you have to project-manage yourself. The point is simply to understand why a phone move and a broadband move tend to happen together on a traditional line, so the change makes sense when your provider explains it.

Why can't I just keep my current FTTC line and port the number?

It's a fair question, and it's the thing a lot of people assume they can do: move the phone number to digital, but keep the FTTC broadband exactly as it is. On a typical WLR-plus-FTTC line, that isn't a real option. Porting the number ceases the old WLR line, and the FTTC service riding on that line goes down with it. So the broadband has to be migrated at the same time, to SOGEA or to full fibre, rather than left untouched.

There's an honest exception worth stating. If you're already on SOGEA, or already on FTTP, there's no WLR phone line sitting underneath your broadband to be ceased, so this "port kills the FTTC" mechanism doesn't apply to you. In that case your phone simply moves to digital voice and your broadband carries on. Providers often handle the whole thing as a single managed migration, so even on a traditional line it can feel seamless, but it's worth knowing that the old WLR-based setup is still being replaced underneath. Understanding that is the difference between a change that feels confusing and one that makes sense.

What are my options if I need to keep a home phone?

Plenty of people still want a proper home phone, and that's entirely fine. Digital voice gives you one. The question is what it runs over, and that comes down to what's available at your address.

• Full fibre (FTTP). The best option where it's available. Digital voice runs over a fast, reliable fibre line, and you get a big broadband upgrade at the same time. Our what is full fibre guide explains what to expect.
• SOGEA. Standalone broadband on the old cabinet network, with digital voice on top. A sensible choice where full fibre hasn't reached you yet but the cabinet network is solid.
• 4G or 5G home broadband. Where neither fibre option fits your address, 4G or 5G home broadband can carry the same digital voice service over the mobile network, so you can keep a home phone without a fibre line reaching the property.

Whichever route fits, keeping your existing landline number is almost always possible: it's ported across to the new service so people can still reach you on the number you've always had. The simplest way to see which options apply to you is to check what's available at your address.

What happens to alarms, care devices, and anything plugged into the phone socket?

This is the most important section on the page, so we'll be plain about it. A digital voice phone does not work in a power cut unless there is a battery backup unit in place. That's because digital voice relies on your broadband and on mains power, whereas the old analogue phone drew its power down the line itself and kept working when the lights went out. It isn't a flaw in any one provider's service, it's simply how the technology differs.

That matters enormously for anyone who has a device plugged into the phone socket beyond an ordinary handset. Telecare alarms, care pendants, personal alarms, fall detectors, and some medical or monitored security devices all traditionally used the analogue line. If you, or someone in the household, relies on one of these, you must tell your provider before the migration so the device can be tested, reconfigured, or replaced with a version designed for digital. Do not assume it will keep working on its own.

If this applies to you, or to a relative you're helping, please read our support for vulnerable customers page. It explains the extra care we take, including arranging suitable backup and making sure care devices are accounted for before anything changes. Flagging a care device early is the single most useful thing you can do ahead of a switch.

What should I do now, and what should I wait for my provider to arrange?

The reassuring truth is that most of this is your provider's job, not yours. They will contact you before your line is migrated, explain how your phone and broadband will work afterwards, and arrange the changeover. You don't need to do anything dramatic today, and your phone won't stop working without warning.

That said, there are a few sensible things you can do now, and one or two are genuinely important:

• Check for care devices and alarms. Walk round and look at what's plugged into the phone socket. If there's a telecare alarm, care pendant, or similar, flag it to your provider early. This is the one thing not to leave.
• Note who relies on the phone in an emergency. If anyone in the home would need to call for help in a power cut, mention it, so backup can be arranged.
• Check what's available at your address. Knowing whether full fibre, SOGEA, or 4G/5G fits your home helps you understand your options before the conversation.
• Decide your timing. You can wait for your provider to contact you, or, if you'd rather get it done on your own calmer schedule, you can move sooner. Either is fine.
• Keep your number front of mind. If you switch provider as part of the move, make sure your existing landline number is included so it travels with you.

If you'd rather make the move on your own timing than wait, you can check availability at your address and we'll handle the change for you, phone and broadband together, number kept, care devices accounted for. Our UK support team is there if you want to talk it through with a person first.

Frequently asked questions about the PSTN switch-off