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How to prepare for the great PSTN/ISDN Switch-off

In 2017, BT announced they would be switching off the Public Switched Telephone Network (PSTN) and Integrated Services Digital Network (ISDN). These will eventually be fully replaced by an internet-based, or IP network. BT aim to have the phone networks replaced nationwide by 2025.

This is a huge step for the telecoms industry. There are many companies that have already made the switch – particularly since the ‘new normal’ of remote working. However, there are many businesses that will need to make network changes to ensure they are prepared.

BDR Group provides award-winning business solutions for companies of all shapes and sizes across the UK, Europe and America. Our company and partners can bring your business up to modern standards across the board. We will ensure that you are prepared for both before and after the switch-off. To grow your business, head to our contact us page and book a free consultation.

What are PSTN and ISDN lines?

PSTN is an older technology, operating under the same principles of the first ever public phone network. It uses analogue voice data, sent via copper cable phone lines.

ISDN is a more recent technology from the late 1980s that sends both voice and data services over digital lines at the same time. ISDN was the standard system for years, but now more than ever, companies need high bandwidth to support videoconferencing and cloud-based work-sharing.

In short, PSTN and ISDN lines power a huge range of services, including phone landlines, alarms, CCTV and door entry systems. The switch-off has begun, meaning that all of these services will need to have moved over to Internet Protocol (IP) networks by December 2025.

What does the switch-off mean for me? 

This depends on how reliant your business is on these pre-existing networks. It may well be that your telephones, security systems, intercoms, alarms or access systems are being hosted by the old network.

As the switch-off date draws nearer and nearer, we would strongly advise taking these three steps to check your network before they’ve called time on the PSTN network:

Step 1:

Check exactly what analogue services your company is still using. Then you’ll know what you need to phase out. If you are unsure, book a discussion to speak to one of our team members.

Step 2:

What services are you going to need to transfer to IP? You’ll need bandwidth and speeds that can handle the additional burden.

Step 3:

Choose your IP communication and connectivity services and make the changes if necessary.

BDR Group and our partners provide solutions for public and private sector businesses of all shapes and sizes. We can make your switch easy and stress-free.

The switch-off plans from BT Openreach


BT announces that the PSTN & ISDN networks will be switched off by December 2025


Openreach improve their Fibre First strategy and the UK begins the mass roll-out of Voice over Internet Protocol (VoIP) services. 2 million businesses are estimated to need to make the switch by 2025.


Openreach tests their stop sell of Wholesale Line Rental (WLR) products in certain UK cities, beginning in Salisbury.


WLR products that rely on the PSTN are no longer sold by Openreach.


In December, the PSTN and ISDN networks are no longer active.

Why is PSTN/ISDN being switched off?

BT state that they have made the decision to switch-off the PSTN and ISDN lines for a number of reasons. The main one is that the demand for using the legacy lines has plummeted in recent years. It is also extremely expensive for BT to maintain those legacy lines alongside their other services.

Openreach have been rolling out fibre services for well over a decade now, putting the UK in a good position for the switch. They believe that the UK’s infrastructure is now stable enough to operate purely via digital networks.

Checking what might be using your phone line

The legacy network may be playing host to a range of features across your company – telephones, CCTV systems, alarms and entry systems to name a few.

There may be an old telephone in your warehouse or a spare office room, or an outdated intercom network that is still connected to the PSTN/ISDN networks. It’s worth checking which of these are still in use.  You want to make sure your company doesn’t get caught out when December 2025 finally arrives, which is not so far away now.

What is PSTN/ISDN being replaced with?

Once the PSTN and ISDN networks have been switched off, telephone systems will operate with mainly Voice over Internet Protocol (VoIP) and cloud-based services. These only require you have a good internet connection to be able to work.

If you are moving over from analogue phones then you will save money from no longer having to pay for expensive analogue line telephone bills. With VoIP you will likely benefit from better call quality too.

Hardware for after the switch-off

Depending on the size of your business, you may need some new hardware that facilitates the hosting of VoIP calls or none at all! If you are moving a security network, alarm system or intercom system over to an IP network however, there may be a larger package that you will need.

Head to our contact page to discuss the range of services that we accommodate. Whatever you communication and connectivity needs, we’re here to help. You can speak with a member of the team by calling 0800 975 3000



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