4 steps to replacing your ISDN phone system

And the benefits it brings

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As you may or may not know, BT Openreach is in the process of switching off the Public Switched Telephone Network (PSTN), which is the copper wire connectivity and phone network running beneath our feet, connecting the UK. This means that any businesses still using these services will find their phone lines being shut off by December 2025. As you can imagine, this could have a catastrophic impact on your company, stopping your phones, fire alarms, CCTV cameras and lifts from working. So looking for an alternative telephony solution before the switch off is important. It seems like a long time away, but you’ll need to act now, before you get stuck. This doesn’t however need to be a difficult or daunting task with the right telecoms partner.

What will I need to replace my PSTN line?

– A trusted telecoms partner to help you with the transition
– Internet connectivity – lots of options from FTTC/FTTP to Fibre Ethernet depending on your requirements
– An internet-based phone system (allowing you to keep your existing numbers)

Step 1. Assess your business’ needs and current solution

Assess how your current system is working – is it perfect for what you need, or are there any improvements that could be made? You can then build these improvements and requirements into your new solution. Are you anticipating growth? Are you launching a chatbot or other services that you’ll need to be able to manage?

Asking yourself these questions and looking at future business projects will make sure you have both current and future needs in mind when it comes to talking to potential telecoms providers.

Step 2. Finding and choosing the right telecoms partner

Like when looking for any new supplier, you want to make sure you choose an expert for the task in hand. So, find a provider who is a specialist in building telephony solutions. Talk to them openly about your needs and any niggles you have with your current solution, then work together to explore ways to make your colleagues’ and customers’ lives easier.

Take time to look at the suppliers’ customers, are they similar to you with similar challenges? Explore their product features and functions to make sure they can support you as your needs change and of course, make sure that they have a great customer service ethos and are able to support you in the way you need.

Another important factor is cultural fit and alignment – will they be easy to work with, are they ‘your sort of people’? If you’re going to be entering into a long-term partnership, the relationship and communications will definitely be smoother if you like each other from the outset.

Finally it’s worth selecting a partner that can support you on both the telephony and connectivity as they’re so intrinsically linked nowadays. Fast and reliable connectivity will provide you with a superior voice experience so having a combined solution designed and implemented from the outset is definitely the way to go, plus a support and single service makes life easier.

Step 3. Secure your broadband

Cloud-based systems will only run as well as your broadband connectivity, so this is an especially important step. There are loads broadband options available depending on what industry your business is in, your size, your location, etc. It can be difficult understanding which internet option and speeds are best for you, so this blog will help you to understand your broadband and make the right choice for your business’s needs. Having a disaster recovery plan (backup internet access) will also help to ensure you’re never disconnected from your customers. This is something that your partner should bring up, but if not, make sure you discuss this.

Step 4. Choose your new phone system

There are many options for phone systems. Start by looking at your current system and considering what features and hardware you like and want to keep. If you’re happy to move to a completely cloud-based phone system, a VoIP solution is what you’re looking for. VoIP phone systems are purchased in ‘seats’ so, one person making calls would be one seat, which makes it an easily scalable solution. If you’re anticipating growth or aren’t sure how many seats to get, your trusted telecoms partner will be able to advise based on how many people need phones or are making calls at any time.

However, if you’re tied into a contract with your on-premises PBX, or you don’t want to get rid of your PBX due to recent investment, you can alternatively use SIP Trunking to help you switch to a cloud-based phone solution. SIP Trunking still uses your PBX but doesn’t connect to the copper phone lines.

There are many benefits to having a VoIP or cloud telephony solution, such as scalability, easy call recording, advanced reporting on call statistics, international call plans if you make frequent calls internationally, Microsoft Teams integration, CRM integration, and loads more.


Will I pay more for broadband and telephony after the ISDN/PSTN switch off?

Businesses using ISDN to call often see much higher charges for calls than those using more modern cloud phone solutions. Many businesses also have good connectivity in place already, and IP-based voice services can be added with SIP trunks, so there are good opportunities for many to save money.


As mentioned, this process can seem daunting, however with the right telecoms partner it really can be a seamless transition. If you’re still using ISDN/PSTN lines, or want to move to a cloud telephony solution, call us today to talk through your options.

Here are some other resources to help you:

VoIP phone systems

Host your business telephone system over the internet and take advantage of powerful call management features to improve your communications efficiency and customer experience.

Read more

SIP Trunking

Get the convenience of a virtual line through your existing PBX system and enjoy the convenience of flexible and reliable voice calls.

Read more

Microsoft Teams Calling

Conveniently join video meetings and make video calls through your cloud-based VoIP phone system with our Microsoft Teams add-on module.

Read more