The Integrated Services Digital Network (ISDN), once the global backbone of voice and video communications, is set to be switched off by BT by 2025. ISDN was first introduced in the mid 80s, allowing BT customers to shift old landlines to digital and communicate at (at the time) rapid speeds.

A lot has changed since then. Despite ISDN lines being overhauled in the years since, they can’t compete with faster broadband internet connections such as DSL and WAN. Couple this with BT’s own focus on voice over internet protocol (VoIP) and it’s easy to see why ISDN is no longer a viable option for the modern organisation’s telephony.

2025 may seem like the distant future but the road to no ISDN has already begun; during the next five years BT plans to permanently hit stop on new ISDN orders. If your ISDN contract is coming to an end, you’re looking to supercharge your company-wide communications, or you simply don’t want to be scrambling to find a replacement system at the final hour, take a look at our four steps to help you future-proof your business and choose the right alternative for your organisation.


With the end of ISDN in sight, and the phase out already having officially begun this year, it’s imperative to find out when your ISDN contract is up and say no to an auto-renewal. Whether you’re contractually obligated for another four years, or you’re able to end your contract soon and get ahead of the curve when it comes to ditching ISDN, it’s important to know when you can adopt a new service, and prepare, research and execute in due course.


The last thing you want to do is use this opportunity to revitalise your setup by incorporating anything that will become legacy in a few years. This year has thrown huge challenges to CIOs and their teams when it comes to enabling remote workers, keeping productivity high, and providing the best possible communication tools in lieu of the office so, if you’re thinking about moving from ISDN sooner rather than later, ask yourself what features does your business need now and in the future? What add-ons will empower your increasingly remote workforce? Will plans to change your premises have an impact? And, to make sure it’s a seamless transition, what trusted partners are out there with the skills and knowledge to help you along the way?


So, what are you swapping your ISDN out for? With several choices available, businesses making the switch need to choose the service that fits their unique business needs, keeps productivity and communication at a high, and provides the most bang for their buck, be it VoIP or SIP Trunks.

Hosted VoIP is a cloud-based phone system built to replace the physical phone system of yesteryear, and is a good choice for those looking to ditch an on-premises phone system and discover new benefits like scalability, flexibility, and functionality. All VoIP calls are made over an internet connection, so it’s important to make sure you have enough bandwidth to support this route.

SIP Trunks, on the other hand, is the natural choice for those looking for a cheaper, more scalable, internet-based phone system that can operate on existing telephone systems. Compared to current ISDN phone lines, SIP offers businesses faster, better quality calls at a cheaper price point and the ability to add and remove lines with ease. SIP can also operate on a cloud-based telephony system. This is ideal for an increasingly mobile workforce, and can even be managed from one centralised panel. Businesses looking to leverage their current on-premises phone system must first check that their kit can be upgraded to work with SIP Trunks.


Whether you have a strong idea of what post-ISDN solution is right for you, or you need someone to walk you through the ins and outs of SIP and VoIP, the right partner is a vital asset in not only transitioning but making sure you’re making the most of your new telephony system for years to come. A trusted partner with the right expertise and experience can talk you through price points, delivery dates, hardware, the resources needed, and just about anything else you could possibly need, such as industry developments and other available support. A great partner will not only make your transition easier, they’ll remain by your side for any questions or queries you have post-deployment.

You may have time to think about it, but why risk the frantic scramble 12 months before switchoff? Failing to prepare could mean you turn to, and are stuck with, the wrong solution for your business. Act now and ensure you have the right cloud-based telephony system, with all the right benefits, from the right partner.

Speak to Comtec today and find out how we can help you embrace the cloud, ditch your legacy infrastructure, and get ahead of the ISDN switchoff. We promise a quick, simple and painless transition with zero outages in the process.