Why ISDN lines are shutting down and what is the alternative?

The copper based PSTN and ISDN network that has historically delivered the UK’s telephone service is currently being phased out. By 2025, it will be completely shut down. Changing technology and increasing demand means that these networks are no longer able to deliver the volume or quality of voice data needed. Increasingly, voice calls are being made over the internet. This is often known as VoIP and makes use of Internet connectivity.

While the PSTN network is almost as old as the telephone network itself, ISDN dates back to the 1980s, and it’s this switch-off that is most likely to impact on ordinary and business users.

What is ISDN?

ISDN stands for Integrated Services Digital Network. This is a circuit-switched telephone network system that uses a digital line to transmit data and voice. It’s a set of communication standards that provides network services over the circuits of the traditional PSTN. It was introduced by BT in 1986 and updated old fashioned landlines to digital lines. It added features that weren’t available on a classic telephone network.

Why is it being phased out?

While ISDN was groundbreaking for the time and represented a significant upgrade to the old system, it has since been superseded by new technologies. ISDN isn’t able to cope either with the scale or complexity of the modern digital era. Big market operators such as BT and Deutsche Telekom have been investing heavily in VoIP over recent years. Operators are increasingly focused on providing services for the evolving business needs of the future. It doesn’t have the flexibility or capacity to cope with the changing demands brought about by technological innovation. Put simply, ISDN isn’t up to meeting the requirements of the ongoing digital transformation.

What are the alternatives to ISDN?

If your business hasn’t looked at alternatives to ISDN then it’s time to begin doing so. The ISDN switch-off can’t be ignored but the good news is that the alternatives available offer a superior service better suited to changing business demands.

The principal alternatives to ISDN is hosted voice over internet protocol (VoiP).

What is VoIP?

Hosted Voice over Internet Protocol (VoIP) is an increasingly popular business protocol. It’s a telephone system that’s based in the cloud. This replaces the older site-based telephone systems and delivers a range of additional business advantages for users.

It works by changing voice into a data packet, in a similar way as email does with text, before transferring it in an instant to the recipient user. This means that you can have a telephone system without any of the on-premises hardware required by a traditional system.

It’s an excellent alternative to ISDN for a number of reasons. Firstly, it’s incredibly easy to scale up or down as your company grows or looks to find efficiencies. There are also no geographical restrictions, which means you can have the same user experience no matter where you are in the world.

Cost Savings

VoiP offers cost savings for users. All UK local, national and mobile calls are usually included in the package. Because you don’t need expensive hardware you save money compared to the old ISDN technology.


As well as the ability to scale up and grow with your business, users are able to work from anywhere with a consistency of experience. They can access the cloud-based VoiP system on the go using any device, such as a laptop, mobile, Mac or iPad.


There is no single point of failure for VoiP technology which makes it much less susceptible to critical failure and serious downtime. If things go wrong there is maintenance support and a range of recovery options.

Easy maintenance

Because VoiP doesn’t need much in the way of on-site equipment, the maintenance requirements are greatly reduced. This reduces the amount of maintenance required and because you manage the entire system centrally, problems can be resolved remotely.

Managed hosted telephony from One Tech UK

ONETECHUK can make sure your business is ready for the ISDN switch-off. Our industry-leading hosted telephony services are a flexible and cost-effective solution. Calls are made and received through the cloud using mobile, IP handsets and other devices, all of which run through a secure data centre.


Call 0333 800 1313 or email [email protected] to find out how you can save money and future-proof your telephony.

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