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The 2025 PSTN Switch-Off & Your Business’s Alarm Monitoring

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Last Updated on 10 March 2023.

Remember the switch from Analogue TV to Digital/Freeview?

Well, the same thing’s going to happen – but this time, with our phone network.

This is a must-read for business owners and managers, as this change is going to affect everyone, but it’s especially important if you rely on alarm monitoring for your fire and/or intruder alarm.

Got any questions? Give us a bell on 01277 724 653 and we’ll be happy to help!

Here’s what we’ll be covering:

1 – A brief synopsis of what’s happening 2 – What is PSDN and ISDN?
3 – When is the switch to VoIP happening? 4 – Who is affected by the switch?
5 – Why is the switch happening in the first place? 6 – Why should I make the switch to VoIP now instead of later?
7 – Is VoIP secure? 8 – What will happen to my fire/intruder alarm monitoring when the switch happens?
9 – Can BT help me to make sure my alarm monitoring works and signalling is reinstated? 10 – What are my options?

A brief synopsis of what’s happening

The communications and telecoms industry has evolved massively in the last 50 years, largely down to our reliance on the Internet and the expansion of fibre broadband. (Imagine if we had to live through pandemic life in lockdown with dial-up?!)

Now, a new technological revolution is on the horizon. And that’s the end of PSTN (Public Switched Telephone Network, part of the Wholesale Line Rental (WLR) product family) and the rise of voice over IP (otherwise known as Voice Over Internet Protocol, or VoIP).

In other words, we’re going ALL IP and our analogue phone network will become a thing of the past. We’re seeing the same thing happening over mobile networks with 2G and 3G being replaced by 4G and 5G as the industry standard.

What is PSTN and ISDN?

PTSN (Public Switched Telephone Network) is your traditional phone line that transports its data in an analogue fashion using copper phone lines. This is pretty much the way phone networks have been designed and used since the 19th Century!

Compare that to ISDN and you’ll notice this is quite the upgrade. ISDN (Integrated Services Digital Network) is the original high-speed Internet service; the prelude, if you like, to VoIP. This still uses a telephone-based network system, but it can transmit data whilst allowing you to have a phone call simultaneously, without the need to miss a call to log on to the Internet or stop browsing so you can make a call.

The upgrade to VoIP is a whole other ball game!

Now, let’s dive into the meatier questions I know you have about this switch…

When is the switch to VoIP happening?

By the end of 2025. That means when we wake up on 1st January 2026, there will be no more analogue, and all calls and call signalling will happen solely via the Internet and not those old copper wires.

But that doesn’t mean you don’t have anything to do until then! In September 2023, there will be a national stop-sell. This means there’ll be no new products operating with PSTN, but it also means that there can be no system takeovers or bandwidth modifications.

PSTN lines have already started to disappear, which can affect older signalling systems still relying on analogue lines. September 2023 is the final deadline for national stop-sell, but it is being rolled out area-by-area once they hit 75% Fibre coverage, so it could hit you before then. Salisbury, for example, became the first stop-sell area back in December 2020.

Click here to see when your area will go into ‘stop-sell’ as part of the BT Openreach project for priority exchanges.

The Government, and indeed BT, are encouraging people make the switch as soon as they can, or at least make preparations to do so in the near future. There’s a lot of work to do. According to BT, there are around 15 million lines in the UK which need changing. Doing the maths on that means that to meet the deadline by the end of 202, they’d have to upgrade 60,000 lines a week, or 240,000 a month!

Who is affected by the switch to VoIP?

This change to communicating on a 21st century network is going to affect all businesses in the UK currently relying on ISDN (Integrated Services Digital Network) or PSTN (Public Switched Telephone Network).

Around 42% of SMEs report to still be using analogue lines which equates to around 2.4 million businesses across the UK. But it’s not just small businesses; around a third of larger companies still haven’t made the switch.

Of course, businesses have had a lot to contend with, including Brexit and Covid-19, so for many this has sat low on the priority list. The reality is, the change is coming, so planning and budgeting for it is essential. 2025 seems like a while away, but with the national stop-sell occurring from now until its deadline in 2023, business owners think they have more time than they actually have.

Why is the PSTN switch happening in the first place?

The change is happening for a variety of reasons. Parts are becoming obsolete and harder to source, which means it’s less cost efficient and harder to maintain. Another huge reason is because of our increased reliance on the Internet to transmit data.

Back in the 1970s when communicating over telephone networks came into their element, and then when computers and fax machines operated over the phone line, this was ideal for what people used it for and needed back then. Then in the 1990s came ISDN (Integrated Services Digital Network) before moving on to total Internet-based communications with broadband.

It’s been a very natural progression so it’s not surprising that this change is happening, because, quite simply, we’re stretching ISDN and PSTN far too thin for what it’s actually capable of doing, and the costs far outweigh the benefits.

Why should I make the switch to VoIP now instead of later?

Moving to VoIP and making the switch from analogue now can mean businesses can start to take advantage of savings. You’re going to have to make the switch, and it’s one thing to delay the inevitable, but why would you if you could make savings as well?

Research by found that the average saving for small businesses which switched was ‘31% of total telephony costs when compared to ISN lines each year’. Line costs are lower and scaling your business up or down is super easy and fast.

When it comes to your alarm monitoring, you’ll also find that the annual subscription for this will be cheaper, too, so it’s well worth opting to future-proof now.

There is also another factor to consider, especially when it comes to alarm monitoring.

And that’s to consider Police and insurance policy conditions. Some businesses have intruder and/or fire alarm monitoring for peace of mind. Other businesses simply have to have it as part of their insurance agreement; for example, a jeweller, or a warehouse containing large amounts of expensive stock. A lapse in the functionality of a system or signal integrity could have insurance implications for its validity and/or if you need to make a claim. If you have questions or concerns about this, do contact your insurance provider.

Is VoIP secure?

You might’ve heard some Chinese whispers that PSTN is reliable, and broadband isn’t, but this simply isn’t true. This argument has even been fuelled by security companies who aren’t keen to lose the nice chunky PSTN-based recurring revenue! Most businesses have security measures such as VPNs (Virtual Private Network) and other methods of encryption and security checks nowadays anyway.

What will happen to my intruder/fire alarm monitoring when the switch happens?

If you’ve already made the switch from analogue PSTN then your alarm should work as normal, and the Alarm Receiving Centre (ARC) will be notified as they usually would when the alarm activates to prompt the next action (be it to notify you/designated key holders or the police/fire brigade).

If you’ve not made the switch, there will be a signal failure which means the ARC will not be notified upon alarm activation. Not ideal!

But it’s not necessarily the 1st January 2026 that you’ll find this out if you’ve done nothing about it – the end of 2025 is the deadline for everyone to have switched, so it’s likely your area will have already pulled the plug on PSTN by then.

There are around 4 million fire and security systems which communicate to Alarm Receiving Centres (ARCs). So, you’re not alone in this.

If you don’t upgrade your signalling device within your fire or security system to one that no longer depends on PTSN, 2G or 3G to transmit signalling for alarm activation notification to the ARC, then your monitoring will be virtually non-existent. You will still be affected even with dual-path systems (i.e. which rely on both IP and PTSN – the phone line and Internet – to transmit the signal).

(Just to be clear here, you can upgrade your signalling device for your alarm monitoring without making the full VoIP switch for your business’s phone network – the two aren’t hand in hand – but you’ll have to consider doing both anyway!)

Click here to learn more about fire alarm monitoring.

Click here to learn more about intruder alarm monitoring.

Can BT help me with my alarm to make sure the monitoring works and signalling is reinstated with VoIP?

Unfortunately, BT will not touch your alarm equipment as a matter of protocol. It is down to your provider (i.e. us!) to upgrade this for you and get your alarm signalling up-and-running again.

What are my options?

For your phone system…

You will have two options:

  • Replace your existing phone
  • Purchase a VoIP device – your analogue phone will plug into this device, which will convert it to a digital signal

So, unless you have a great sentimental attachment to your existing phone, the first option may be the best bet.

For your alarm system(s)…

  • There are short-term solutions such as analogue to IP convertors

You can, for instance, get an MCM (Modem Capture Module) for any existing control panel that uses a PSTN line. This module converts the signal and provides the 50v monitoring the panel will be looking for from a phone line.

However, this is not sustainable and is unlikely to resolve things like round-trip time delays (the signal loop between the alarm and the ARC) or back-up power.

  • Upgrade your signalling device for your monitoring

WFP highly recommends Dualcom Pro as the monitoring device of choice, which uses two radio paths to transmit signals.

We aim to have upgraded all of our customers’ signalling devices well before these changes occur. (You will also be contacted, likely by BT or your local council, about when the change is coming to your area, prompting you to take immediate action.)

If we haven’t yet upgraded your signalling, please contact our team today for a quote and we can schedule this in to be done during your next maintenance visit to save on the cost of an additional visit.

And if you’re not yet a customer of ours, we can provide you with the cost to upgrade your monitoring device for your fire and/or intruder alarm alongside a maintenance, too!


Contact us today using the details below!

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