The switch-off deadline for the PSTN is 31 January 2027. PSTN is the old analogue phone network, including ISDN2 and ISDN30, and the WLR line rental products that run on it. That’s not far away now, so if you’re not 100% certain all your business lines have moved to a digital alternative, such as VoIP over SOGEA or FTTP broadband, it’s time to make sure you’re sure!
The likelihood is your phone lines will be fine, since most main business phone systems transitioned long ago. We've found that the issue for businesses is more often the background lines that easily get forgotten. Think lift phones, alarm diallers, door entry, card machines, fax and franking machines. The ones that were added years ago, moved between providers, bundled into packages, or inherited with a building or site. This is especially common after an office move or acquisition, when inherited sites bring lines nobody on your team has ever seen.
I asked our MD Nick Bass about the switch-off, and he put it plainly;
“We’ve been advising customers for a few years now to plan the move away from analogue. The risk isn’t usually the main phone system, it’s the hidden lines tied to alarms, emergency phones, lifts and older kit. If you wait until the last minute, you’re far more likely to miss something critical.”
He also highlighted that legacy lines are already hitting customers in the pocket;
“We’re already seeing legacy products getting hit with significant price rises as providers push people to move. A planned transition gives you control — the right solution, proper testing, and no nasty surprises when the old network goes.
The time to act is now. Alarm, lift and equipment suppliers are all heading for the same deadline, so engineer slots and replacement units will get harder to book the closer we get to January. We're not trying to panic people, but a proper migration takes discovery, planning, and testing. The earlier you start, the smoother it is.”
Your next step: account for every line
If you're not 100% sure you've transitioned all your lines, here's what to do next. Produce a simple “account for every line” checklist. You don’t need a 40-page telecoms audit. You need a clean, practical starting point.
1) Ask: "Do we know what every line does?"
For each number / circuit you’re billed for, try to answer:
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What is this line connected to?
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Where is it physically (site + location if known)?
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Who “owns” it internally (name/role)?
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Who else is involved (provider, maintainer, landlord, alarm company, lift company, etc.)? Alarm, lift and card machine suppliers often own both the line and the kit, so contact them now.
If you can’t answer those quickly, that’s a flag.
2) If you’re unsure, check your bills for numbers you don’t recognise
In our experience, a lot of “forgotten lines” show up here first.
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Look for numbers you don’t recognise
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Look for bundles/packages where the line is basically hidden
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Look for anything that looks like a legacy add-on that nobody has revisited
It’s surprisingly normal to be renting a line as part of a bundle without realising what it’s supporting.
3) For anything unclear, ask the maintainer/provider to explain it in plain English
If there's anything on the list you just built that you're not 100% sure about, ask your provider or providers.
Ask them to explain:
- what type of line it is
- whether it will survive the analogue switch off
- what alternatives they provide
- whether you can keep your existing phone numbers
Be especially careful with alarm and lift lines. Many of these devices were built for analogue and don’t work reliably through a standard VoIP adapter. The answer may be a replacement unit or a mobile (4G) solution rather than a straight swap, so ask the supplier what they recommend.
If this brings something up, ask about what alternatives they are providing. Get pricing from them - for monthlies and upfronts - but don't switch straight away. It's important to plan any big technology changes. Get clarity and get it written down.
4) Don't forget power and resillience
Copper phone lines kept working in a power cut. Broadband and VoIP don’t, because they need mains power and a working router. That matters most for life-safety lines such as lift phones and alarms.
Where a line is critical, consider battery backup for the router and any adapters, and a 4G failover so you stay connected if your broadband drops.
5) Plan the move, then test it properly
We believe strongly that a migration isn’t complete until it’s tested as live .
Whatever your lines support, the transition should include:
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a clear plan
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a cutover date
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a test plan
- testing during a simulated power cut or broadband outage
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someone responsible for signing it off
What a head start?
Download our printable or fillable "account for every line" PDF checklist
If you find a line you’re not sure about, get in touch - we’ll help you figure it out.
If you find a number you can’t identify, or you’ve got a system that nobody can clearly explain, that’s exactly where we can help.
We can help you:
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identify what a line is actually for
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work out whether it’s affected by PSTN switch-off
- advise on telecoms and connectivity options that keep you covered if something goes wrong
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map a sensible migration plan (without drama)
- make sure it’s tested and signed off properly
FAQs
What happens on 31 January 2027?
The old analogue network is switched off, so any line still relying on it, including ISDN, will stop working.
If we use 3CX or Teams Phone, are we fine?
Your main phone system probably is, but check everything else: alarms, lifts, door entry and card machines.
Will my alarm or lift phone still work?
Not necessarily. Ask the supplier, and make sure any replacement is tested.
