What is the PSTN & ISDN Switch Off?
Here's everything the public sector needs to know
This section of the document will act as your central resource providing background to, and the latest information about the changes ahead, as BT Openreach prepares to retire the Public Switched Telephone Network (PSTN) and Integrated Services Digital Network (ISDN). Sometimes this is referred to as the ‘National Copper Switch Off’.
This change is important to the public sector as there's lots of critical technology that could be impacted: from property buzzers, to lifelines, monitors and alarms.
TalkTalk Business is fully committed to supporting our public Sector customers through this journey. Due to our extensive network investments, we’re able to offer more options than other providers, helping your business stay connected and embrace the new digital future with our range of alternative solutions.
We have already switched to fibre, or an alternative.
We have a strategy, or have started to define one.
We are yet to make a plan and/or we are not sure of the consequences.
Put simply, the PSTN allows users to make and receive phone calls and is comprised of BT Telephone exchanges. The network was installed in the 1980s and is now very outdated.
Integrated Services Digital Network (ISDN) provides digital communication voice and data, and runs over the PSTN.
In 2017, BT Openreach announced its intention to retire the PSTN through withdrawing Wholesale Line Rental (WLR) lines (which connect to the PSTN BT Openreach). The Switch Off is happening to make way for new technologies. Although the PSTN was installed in the 1980s, the network was first set up over 100 years ago and is now very outdated. ISDN is an upgraded version of PSTN and offers faster speeds and a better quality, but the switch off takes place at the same time.
From September 2023, all UK service providers are no longer offering new lines that connect to the PSTN. However, existing customers can continue to use WLR lines until December 2025, with a limited additional time window for some organisations, giving them until 2027.
The PSTN & ISDN network will be completely shut off across the UK in January 2027. So organisations that are reliant on this technology for phone, internet, or critical citizen-centric infrastructure, will need a new solution.
While many organisations are exploring fibre, digital voice and SIP Trunking - there are other solutions for those who need more time to consider long term plans. We explore this in more detail throughout the last section of this document.
