ISDN Switch Off

8th September 2018

Many businesses could suffer an inconvenient rupture in their communication operations if they fail to heed BT’s warning that its PSTN and ISDN networks will be switched off in 2025, leaving its IP network the sole option for businesses seeking a sleek and well-oiled modern phone system.

Therefore, it is well-advised for businesses to act now as the 2025 cut-off point nears. However, why is the ISDN switch off happening and how can companies work towards overcoming this hurdle?

voip vs pstn and isdn

ISDN is not only going – it’s taking PSTN with it

ISDN – or Integrated Services Digital Network, as it can otherwise be called- lets businesses digitally transmit numerous services, including voice and video, simultaneously. As such, it has obvious usefulness for companies eager to draw upon several services at once without interruptions.

However, when originally introduced, ISDN was effectively an improvement on PSTN. This older telecoms technology, alternatively called Public Switched Telephone Network, allowed analogue voice communication over what is now a familiar landline telephone system.

Despite the meaningful advances it brought to PSTN’s standard functionality, ISDN still used the traditional PSTN network. Therefore, it makes sense that BT has put itself on course to switch off both its PSTN and ISDN networks by 2025. However, why is BT so set on axing ISDN in the first place?

Outdated technology with fresher alternatives waiting in the wings

Why would you be tempted to replace a smartphone that you originally bought five years ago? This begins to explain why BT wants to move away from ISDN, which uses lines that, in setup and design, largely match the phone lines originally implemented in the nineteenth century, says Minutehack.

Meanwhile, more sophisticated solutions are emerging for businesses wanting phone systems fit for the modern age. explains that BT faces significant costs in maintaining multiple legacy networks; however, the company would have to maintain just one network if it goes through with its plan to transfer all services, including those of voice, data and video, to IP.

Here, IP refers to the protocol used by SIP and VoIP phone services. IP-based services of both of these types are available from our team here at Planet Telecom – and, once you have switched to such a service, your own company can also expect to make significant cost savings over time.

Is the 2025 cut-off date really set in stone?

There are good reasons to believe that BT could be flexible with its 2025 date for the ISDN switch off. While meeting this deadline would be the last stage in an ISDN phasing-out period also set to include BT ending its sales of ISDN services in 2020, BTcould yet further slow the process.

Today, ISDN remains the most palatable option for many businesses. In early 2017, over 2 million UK-based businesses were still using an ISDN connection – while, in a survey that year, a quarter of UK firms admitted to not knowing about the ISDN switch off.

Therefore, BT will not want to be seen to be abruptly pulling the plug on these companies’ internet connectivity. Before shutting down its ISDN network, BT will need to make sure that it has switched all of its customers to IP services, which will need to be available across the UK well before 2025.

What exactly should your company do before 2025?

With 2025 still several years away, you might be tempted to leave an existing ISDN contract to renew itself automatically. However, in doing so, you could risk your business falling behind.

ITProPortal warns that, with ISDN now deemed a legacy platform, it is likely to attract less investment in future. If you continue with ISDN for your business, you could start noticing drops in the quality of service – due to issues with the network and support infrastructure – well before 2025.

Hence, if your telephony system is awaiting a refresh or upgrade in the next few years, it should be replaced with an IP solution. Also keep in mind that, by exploring the IP options now, you can give yourself time to settle on the best choice of future-proof solution ahead of 2025.

How the Planet Telecom team can step in to help

If you are reticent about giving up the PBX system currently used by your company’s ISDN system, you could hold off adopting a completely internet-based VoIP service by instead choosing SIP trunks. At Planet Telecom, we can provide these; more details are available if you call us on 0800 088 6886.