Everything you need to know about the 2025 switch off

In four years’ time, BT is switching off the ISDN telephone network for good. From that moment on, all your telephone calls will be made over the internet.

That may not sound like such a big deal, but it’s the most fundamental change to telecoms infrastructure in the UK since the 1980s, when ISDN was first introduced. In effect, it means the end of the era of the “landline”, and its total replacement with Voice over Internet Protocol services, usually known as VoIP.

And there’s no getting out of it. If you’re still using ISDN at the end of 2025 you will be forced to migrate to a VoIP service. It’s highly unlikely that BT will extend this deadline, and in fact it has already stopped selling new ISDN lines in a number of areas.

So why do you need to know about the ISDN switch off now? It may be four years off, but you don’t want to get into a situation where you’re forced to adopt a new telephony service that you know little about and that might not be the best fit for your business.

If you start preparing for the switch off now, you can make sure the new system you eventually adopt meets your requirements and gives you all the advantages of flexible, cost-effective VoIP telephony. And having weighed up the pros and cons, you may decide that you want to benefit from a modern telephone system sooner than 2025. Many businesses are already switching to VoIP, and many more will do so in the next couple of years.

That’s why we’ve written this educational guide to the 2025 switch off. Whether you’re ready to adopt a new telephone system now, or just want to be prepared well in advance, it will tell you everything you need to know about the end of ISDN and what comes after it. We hope you find it useful.

What is the 2025 switch off?

When ISDN was first introduced in the 1980s, it was revolutionary. For the first time, voice and data could travel over the same line. But this was before the advent of unified communications, video calling, conferencing and more. The arrival of modern, internet-based communications has stretched the ISDN network to the limit.

But that on its own wouldn’t be enough to persuade BT to jettison ISDN altogether. There needs to be something ready and waiting to replace it. That something is VoIP.

For those who remember the early days of VoIP a couple of decades ago, the prospect may fill you with horror. Back in the early Noughties, the first incarnations of Skype and other VoIP services were unreliable and prone to drop outs. Some businesses would Skype when it came to less important matters, but fall back on ISDN when it came to crucial customer calls. Many of them still do today.

But in that time VoIP calling has been revolutionised. The advance of bandwidth and broadband speeds means that internet-based calling is now efficient, reliable and cost-effective. VoIP can not only do everything ISDN can do, it can offer businesses a lot more besides.

For example, unified communications can put all your communication needs – voice, video, chat, email, etc – in one package. Cloud-based systems let you access your phone system from anywhere, on any device. They let you make and take professional business calls wherever you have an internet connection, using the same telephone number and benefitting from all the call management features that at one time were only available in the office.

For all those reasons, BT has decided that we can do without the ageing ISDN network, which is costing more and more each year to maintain and repair. The switch-off process has already begun, with BT ending new ISDN sales in a couple of areas already and planning to end them everywhere in 2023. The countdown to 2025 has begun and, if nothing else, businesses should be aware of the ticking clock.

What is the 2025 switch off? Find out more in our informative blog

Why checking your telephone bill is so important

With the countdown to 2025 underway, it’s the perfect time to start getting your telephony affairs in order. When you have a better understanding of what you’re actually getting, and how much you’re paying for it, you’ll be in a better position to understand what a VoIP service could do for your business.

That’s why one of the first things we do at Express Telephony for potential customers is ask to see the last bill from their current supplier. We go through it with a fine tooth comb, identifying potential savings and areas where resources could be used more efficiently. We quite often find that businesses are paying for lines or hardware they no longer actually use.

All businesses should do something similar, whether they’re planning on changing suppliers or not. In fact, now is the right time to do it, as employees return after furlough or lockdowns, and you may be considering how to support a permanent remote or semi-remote workforce.

There may be infrastructure or hardware you can now do without. On the other hand, you may need new services to better support remote workers.

By analysing your bill in detail, you’ll get a better understanding of what your telecoms infrastructure actually includes, where you can make it more efficient and where there might be savings to be made. We recommend that you check your bill today.

Here’s much more about checking your telephone bill – and why you should do it

How to claim back unused lines

One of the reasons to do a thorough bill check (see previous section) is to make sure that you use all the ISDN lines that you’re paying for.

It might sound unlikely that a provider is selling you a service you don’t use, but in our long experience it happens more often than you might imagine. It may be that your requirement has reduced, and you have simply forgotten to cancel a line you no longer need. It may be a mistake on the part of the provider, who is charging you for a redundant line.

If you think the mistake is on the part of the provider, you’re perfectly within your rights to claim back the cost of unused lines. We often do this on behalf of our clients, after we’ve discovered discrepancies in a bill from a large telecoms company or ISP.

If you think you may have been charged for services you don’t use:

  • Gather proof. Find out what you do and don’t use, and check your contract to find out if you ordered the extra capacity, or if it has been added to your bill by mistake.
  • Escalate through your provider. Take it up with customer service first – your provider may be quite happy to admit their mistake and refund the money. If not, lodge an official complaint, and keep proof of having done so.
  • Escalate through Ofcom. If your provider proves intransigent, you can turn to Ofcom, the telecoms ombudsman.
It’s worth knowing that one benefit for switching to VoIP is that with internet-based telephony you don’t have to pay for spare capacity you don’t use. VoIP is flexible and scalable, and lets you add and remove users almost instantly, so there’s no need to order extra lines “just in case”.

What is VoIP and do I need to switch now?

Given that all businesses will have to switch to VoIP by the end of 2025, and many are already doing so, the obvious question is what actually is it?

VoIP is an umbrella term for a range of technologies and services that route voice and other data over the internet. Voice data travels over the same pathways as your email and internet traffic, so you only need one line for all your telecoms and connectivity needs.

That can make VoIP more cost-effective than ISDN, and gives it the huge advantage of being available anywhere. Just like your email is available on your desktop, laptop or phone – and in the office, on the train or at home – so is your telephony service. You can tap into many VoIP services from anywhere with an internet connection, and from a dedicated handset (a desk phone) or a softphone app on any of your devices.

VoIP also comes in a number of flavours, with different features and benefits. They include:

  • SIP. SIP (Session Initiation Protocol) Trunking is an affordable, flexible and reliable alternative to traditional telephony that uses your existing PBX to combine a full VoIP phone system with multimedia communications.
  • Unified Communications (UC). UC brings all your business communications tools together in one package, from VoIP and video calls to conferencing, chat and email. It can also include collaboration tools like presence and screen share.
  • Hosted voice. Hosted voice puts all your communications infrastructure in the cloud, which means you no longer have to house, manage and maintain telephony hardware.
Do you need to switch to VoIP now? The simple answer is that, if you’re happy with your current phone system, there’s no need to switch just yet, though you should start to educate yourself on the alternatives available.

But some companies may get significant benefits from switching sooner, and if you’re currently transitioning to more permanent flexible working – including regular remote working – there’s a compelling case to upgrade to VoIP right now.

More on VoIP and whether you’d benefit from switching up today

The differences between copper and fibre technology

If you’re thinking of switching to all-IP communications (VoIP) – and in fact even if you’re not – it’s a good time to review your connectivity solution. ISDN is delivered across the copper telephone network, and basic broadband services use the same technology. But just as ISDN is getting towards end of life, so is copper-based connectivity.

Copper connectivity is also known as ADSL, and it’s been the broadband standard since we all upgraded from dial-up internet all those years ago. ADSL is solid broadband technology, but like ISDN it’s beginning to get a bit long in the tooth.

As you probably know, the upgrade to ADSL is fibre. With fibre, your internet data travels over fibre optic cables, which are much faster and more reliable than copper wires. For most businesses, there are currently three fixed line broadband alternatives:

  • ADSL – based entirely on copper, and with maximum download speeds of up to around 20Mbps.
  • Fibre to the Cabinet (FTTC) – fibre from the internet to your nearest street cabinet, then copper for the last bit of the journey to your premises. Maximum download speeds of up to roughly 80Mbps.
  • Full fibre (FTTP) – end to end fibre, with potential top speeds of 1Gbps and above, though 300Mbps is more common at the moment.

Full fibre is not available everywhere yet, and might be overkill (and expensive) for most small businesses anyway. But with prices that are only marginally more than the cost of ADSL, FTTC is currently the connectivity sweet spot for smaller businesses with normal internet requirements.

FTTC offers a range of benefits over ADSL. Because it’s faster, you can do much more with it, including adopting more cloud services and having more employees online at one time. And when you upgrade to VoIP, FTTC will ensure cleaner, clearer audio and video calling.

So should you upgrade to fibre? Again, the decision depends on your specific circumstances. Express Telephony can help you work out if FTTC is the right investment for your business right now.

Copper vs fibre connectivity: learn more about the differences and what they mean for you

What to look for in a telecoms partner

If you’re thinking of upgrading your communications and connectivity, it’s essential you have the right telecoms partner on board. You need someone who won’t just sell you a solution. They’ll design and support just the right solution for you.

To do that they clearly need expertise in the field and a wide experience of delivering telecoms solutions to businesses like yours. If you’re a small business with 10 employees, you don’t want to be dealing with a provider who’s more interested in servicing large enterprises with 500 employees or more.

Which is why, for many SMEs, the best partner is a small provider rather than a big name ISP. With the latter, a small business is likely to get lost in the crowd, and will always be behind big-spending enterprise customers when it comes to customer service and support.

With the former, you’ll get good local knowledge and personal care. At Express Telephony, every customer gets the same high level of support, regardless of their size or how much they spend with us. We offer all our customers a free IT and telecoms audit to make sure you have the right infrastructure for your needs, and that you’re not paying more than you need to. We take the time to get to know your business in a way a large ISP simply wouldn’t.

For more on what to look for in a telecoms partner, and what you can expect from us, read our blog