ISDN switch off – What is it and what does it mean for businesses?

By December 2025, BT (Openreach) aims to completely retire the UK’s decades-old copper telephony lines. The copper infrastructure is the basis for the UK’s Integrated Services Digital Network (ISDN) and Public Switched Telephone Network (PSTN), meaning that both of these traditional solutions will cease to be available in a few years.

ISDN is widely used to connect business telephone systems to the wider phone network. The PSTN powers most residential phone lines, many small business phone lines, and is used by some businesses to link their alarm systems to monitoring centres.

As a result of this vital role in communications, ISDN switch off, in particular, will have significant ramifications for many UK businesses and necessitate a fundamental change in their comms infrastructure. While the final switch-off is scheduled for the end of 2025, the process will in fact be more gradual than a simple shut down.

In some areas of the UK, the switch off has already begun and is scheduled to proceed in stages over the next few years. In certain areas, BT has already stopped selling copper products and, by September 2023, will stop selling copper products across the entirety of the UK.

The impact for businesses

How ISDN switch off affects a business will be dependent upon that business’ existing communications infrastructure. Over recent years, many businesses have already transitioned to an Internet Protocol (IP) based telephony system, a trend that only accelerated with the rise in remote working during the COVID-19 pandemic.

However, businesses that remain reliant on an ISDN-based telephone infrastructure will need to find an alternative system and then plan and execute a migration to that system before ISDN is switched off in their area.

What to do and options for migrating

The first step in the migration process from ISDN will be for the business to find out when the local copper exchange that their system is on is due to be turned off. This information can be gathered either from Openreach, or from the business’ provider. This will be invaluable in determining the timeframe the business has in which to migrate.

Next, the business should review its existing infrastructure to assess whether there will be a need to upgrade or replace outdated legacy hardware. A technical expert can be vital at this stage in identifying which pieces of hardware can remain in place post-migration, which need to be upgraded and which will need to be entirely replaced.

At this point, it will also be important to assess whether the business’ current internet connection is capable of supporting the added burden of an IP-based telephone system. If not, this will also need to be upgraded.

Then, the business in question will need to consider their future requirements and plans in order to decide what alternative system will work best for them. Issues such as whether the business will continue with widespread (or total) remote working post-pandemic or if it is considering moving premises will be vital to gauging what communications infrastructure is most suitable.

IP systems that can replace ISDN frameworks include cloud-based solutions like Hosted Voice over Internet Protocol (VoIP). Hosted VoIP is a cloud-based telephone system which utilises a business’ internet connection to transmit calls.

Again, consulting with a telecoms provider to assess the most appropriate system can be vitally important, not just to a successful migration, but also to ensuring the business doesn’t rush into a knee-jerk decision to adopt a system that isn’t suitable.

Finally, once all the relevant information regarding the migration has been gathered and an alternative system selected, the business can begin planning for its migration. This will involve scheduling hardware upgrades and pricing and budgeting for the migration.

Benefits of migrating

Migrating to an IP-based phone system may seem like a chore or simply something that a business is compelled to do prior to the ISDN switch off, but business owners should instead view it as an opportunity to improve their company.

An internet-based solution can allow a company to migrate its existing numbers to a system that also enables them to integrate it with new features like video calling and screen sharing. In the age of remote working, this can massively improve a company’s communications.

With a hosted, cloud-based solution like VoIP, companies can also gain enhanced scalability and functionality in their telephone systems, making communications smoother and adding new users quicker and easier. Furthermore, moving to a hosted solution can deliver savings by reducing the maintenance costs of an ISDN system.

Finally, whereas outages on the old, copper-based infrastructure often required costly, time-consuming repairs and could result in lost data, a cloud-based IP solution means that the business’ provider takes responsibility for any maintenance, delivering quicker response times to problems and providing enhanced disaster recovery.