31 July 2018

Since BT announced that they were switching off the UK’s ISDN telephone network, the 2025 deadline is now firmly in sight and the countdown has begun.

12th December 2023 Update – What is the Square One Network’s Approach to the PSTN Switch-off?

Effective from September 5th, 2023, BT Openreach has implemented a nationwide stop-sell of the Public Switched Telephone Network (PSTN), marking a significant step in the transition to advanced technologies. This event signifies the commencement of the phase-out process, leading up to the complete PSTN switch-off scheduled for 2025.

The stop-sell announcement implies that BT Openreach will no longer offer new services based on PSTN as of September 5th, 2023. It’s crucial to note that existing legacy PSTN services can still be used until the final switch-off in 2025. However, during this transition period, acquiring new services or modifying existing ones that rely on ISDN or PSTN will not be possible.

So, what alternatives are available?

In response to the evolving landscape, many businesses are embracing Voice over Internet Protocol (VoIP) technology. Hosted VoIP Phone Systems enables users to make phone calls and transmit data over an internet connection, presenting an opportunity to transition to an all-digital solution and future-proof their business

The decommissioning of PSTN lines signifies a transformative technological shift, and while the prospect of switching may seem daunting, meticulous planning is key. If you have any questions or require assistance, Bristol based Telecommunications Service Provider Square One Network is here to help you navigate this transition effectively.

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What does this mean for your business?

By deciding to phase out the ISDN system, BT have acknowledged that communication has changed and that Internet over Protocol (IP) systems – such as SIP Trunks – is the next big step for businesses. Therefore, BT decided not to invest any more time or money in a system that won’t enhance a business’ ability to communicate.

In addition, the maintenance and running costs of ISDN systems are also the most expensive which means the longer you hold on to your ISDN systems, the more it’ll cost your business. By migrating your ISDN lines to SIP Trunks, you’ll only have to maintain one.

What are SIP Trunks?

Session Initiation Protocol (SIP) trunks is a voice over internet technology which can deliver telephone and video services on a global scale, using computers and mobile devices with a secure internet connection.

The biggest comparison between ISDN and SIP trunks for businesses is cost, as communications between SIP users is free. A study by TalkTalk found that 96% of businesses which had already made the switch were making cost savings. *

It’s Time to Take Action

In early 2017, there were over 2 million businesses still with an ISDN connection in the UK. **

So, whilst the deadline seems quite far away, in fact the move towards cloud-based telephony is happening right now. The more time you can commit to a project, the better it’ll be so it’s important to start thinking about making the move sooner rather than later.

Here’s more information on how to migrate from ISDN to SIP.


* Source: TalkTalk and Censuswide survey based on 1,000 UK decision makers.
** Source: Ofcom.