Getting ready for the PSTN & ISDN Switch Off

Get Switched On about the Switch Off#

Welcome to our PSTN & ISDN Switch Off Hub– your central resource for 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) in 2027.

TalkTalk Business is fully committed to supporting our 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.

On this page you'll find key dates to take note of, simple explanations about the Switch Off and what it means for your business, as well as some frequently asked questions to prepare you for the changes ahead.

Not ready for a post-PSTN & ISDN world? Don’t worry, we have options to keep your business connected and maintaining operational continuity through this period of change.

We'll be regularly updating this page with helpful information to guide you through, so be sure to check back.

PSTN Switch Off Explained#

What is the Public Switched Telephony Network? 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 The network was installed in the 1980s and is now very outdated.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), and they are now offering the following “All-IP” line types to replace WLR:

• SOGEA – Single Order Generic Ethernet Access is Fibre to the Cabinet broadband without the WLR phone line

• SOGFast – the G.Fast variant of SOGEA

• FTTP – Fibre to the Premise broadband

These lines do not connect to the PSTN and require Communications Providers to offer VoiP based services for telephony.

It is important to note that Openreach has not changed the status of Metallic Path Facility (MPF) lines that TalkTalk Business use, and these lines are fully available and not affected by PSTN switch-off.

From September 2023, WLR went into stop-sell. Currently, all UK service providers are will 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 users, giving them until 2027.

Our MPF-based services are unaffected by WLR.

If your business isn’t ready to make the change to Digital Voice, we’ve got you covered. TalkTalk Business can still provide telephony and broadband services over Metallic Path Facility (MPF) as an alternative, as these Openreach lines are unaffected by the PSTN stop-sell, allowing users continued support to existing devices. Keep scrolling for more detail.

What alternative solutions can TalkTalk Business provide?#

TalkTalk Business offers VoIP voice services also called Digital Voice as an alternative to the traditional PSTN.

As Digital Voice is Internet Protocol (IP) based, it works over the broadband connection. VoIP phones must plug into your router/broadband hub or via an adapter.

Digital Voice services offers more features and can be used from more device types than just a telephone. They can integrate with your other IT systems, and enable greater collaboration to your teams, enhancing productivity and time. As well as voice calls, Digital Voice gives you a feature-rich solutions that can be tailored to you and grow with your evolving needs, future-proofing your telephony needs.

To be able to use Digital Voice, you’d need to have one of the following new Openreach line types: SOGEA, SOGFast or FTTP.

Not ready for digital voice?#

If you’re not ready to move to Digital Voice, our customers can still prepare for the 2027 Switch Off with Metallic Path Facility (MPF).

Unlike other providers, TalkTalk Business offers voice services via MPF. This technology utilises the existing copper wires, connecting directly from our equipment in the BT Telephony exchanges to our customers’ premises. This ensures a smooth connection for standard (i.e. non-VoIP-compatible) phones to our own telephony switches.

TalkTalk Business's MPF voice services are therefore unaffected by WLR stop-sell or withdrawal in 2025, which means that we can continue to offer broadband and Fibre to the Cabinet (FTTC) with MPF. MPF FTTC is functionally identical to SOGEA in respect of broadband performance and availability.

MPF is a seamless solution that puts control back in your hands, giving you more time to plan and implement your digital strategy to move onto Digital Voice, when you’re ready.

Are these alternatives widely available?#

TalkTalk Business currently have equipment in 3000+ Openreach exchanges across the UK, which equates to 92% national coverage where customers can or are using MPF.

Where we don't have exchange presence, in the immediate-term, customers can remain on their existing WLR connections till December 2025 from which point they will need Digital Voice options for telephony.

TalkTalk Business also offer IP based telephony options including SIP (Session Initiation Protocol) and hosted voice, Digital Voice solutions.

We're working hard to ensure that all our customers have alternative connectivity solutions available and will continue to share updates as our coverage increases further.

PSTN & ISDN Switch Off FAQs

• What is the PSTN and why is it being switched off?

  The Public Switched Telephony Network (PSTN) is the communications infrastructure that enables voice communication through conventional landline phones in the UK. It is made up of BT Telephone exchanges connected together. Although the current PSTN was installed in the 1980s, the network was first set up over 100 years ago and is now very outdated.

• What is ISDN and why is it being switched off?

  ISDN is an upgraded version of PSTN and offers faster speeds and a better quality. ISDN is more likely to be used by those who need a high-speed internet connection, such as businesses. Access is being switched off at the same time as PSTN comes to an end.

• When is this going to happen?

  It's happening now. BT Openreach announced the retirement of the PSTN (and therefore WLR lines) in 2017. BT Openreach WLR lines connect to the PSTN. WLR lines also connect to ISDN2 and 30 which are also being switched off in the same timeline. As of 5th September 2023, WLR lines are at “stop-sell” stage, ahead of a full planned Switch Off by January 2027.

• What does this mean for the BT telephony service?

  BT only provide Openreach lines, therefore are providing Digital Voice over the new Openreach line types from the 5th September 2023.

• What is Digital Voice?

  Digital Voice calls use Voice over Internet Protocol (VoIP). As Digital Voice is Internet Protocol (IP) based , it works over the broadband connection. VoIP phones must plug into the router/ customers broadband hub or via an adapter. It's a great, cost-effective option with advanced features to help businesses move away from traditional telephone devices in favour of laptops, tablets and mobiles. VoIP becomes the simplified choice, as less hardware is required compared to PSTN and ISDN services.

• What Digital Voice options do TalkTalk Business offer?

  TalkTalk Business offer a range of Digital Voice solutions that stretch all the way up to hundreds of users. We also offer SIP Trunking.

• Which access services and technologies will TalkTalk Business offer in the future?

  We will continue offering MPF-based service within our network footprint, including FTTC which will function identically to SOGEA. This will be advantageous for our customers as they won't need to replace their existing telephone handsets. We'll also be offering FTTP as well as a range of other solutions from alternative providers very soon. We'll provide updates in due course.

• What if I do nothing?

If you do not migrate from the PSTN to alternative communication technologies, you'll likely experience a loss of reliable phone services. As the PSTN is retired, you may face increasing difficulties in making and receiving calls, maintaining connectivity and accessing support for analogue systems.

Ultimately, all connections will no longer work after 31st December, 2026, so you will be left without a functioning phone system. In turn, this could be highly disruptive for your business in terms continuing to serve customers effectively or running normal business functions.