Your top 2025 PSTN questions answered
The Public Switched Telephone Network (PSTN) is being closed in Dec 2025. We have collected the top questions that suppliers and customers have regarding the PSTN 2025 Switch Off.
The Public Switch Telephone Network (PSTN) will reach its end of life in December 2025. The PSTN supports a number of Openreach products which Communication Providers (CPs) purchase at regulated pricing and often sell to businesses and consumers, wrapped up in their own line rental, broadband and call package deal.
These include Wholesale Line Rental (WLR), Shared Metallic Path Facility (SMPF) Broadband and Integrated Services Digital Network (ISDN). At the end of December 2025 traditional telephony, including fixed lines and services in the Public Switch Telephone Network (PSTN) will be switched off and withdrawn from service.
Openreach is looking to maintain a high availability fibre first network, as a result their legacy infrastructure (traditional telephony) and equipment serving the PSTN is now ageing and becoming more difficult to maintain, prompting Openreach to withdraw its current product line by 2025.
Openreach are adamant the December 2025 deadline is set in stone. PSTN Lines that have not migrated to alterative services in April 2025 will be deemed as Orphaned Assets and Openreach intend to work with CPs to identify and migrate customers to alternative products by the December 2025 deadline.
The Public Switch Telephone Network currently supports WLR, ISDN2 and ISDN30, Local Loop Unbundling Shared Metallic Path Facilities (LLUSMPF), Narrowband Line Share and Classic Products. This will in addition affect products such as Asymmetrical Digital Subscriber Lines (ADSL) Broadband and Fibre to the Cabinet (FTTC) Broadband. This is because the underlying line product is being withdrawn, therefore there is no underlying WLR telephone service to support the broadband.
Openreach started withdrawing their services initially from their two trial sites Salisbury and Mildenhall.
The Salisbury exchange was used for the FTTP Exchange Project and follows the FTTP Exchange Rollout timeline while the Mildenhall exchange, is being used for the National PSTN Withdrawal and follows the National PSTN Closure timeline.
The Sailsbury Exchange started from 1 December 2020 and the end-of-life date for Salisbury is 16 December 2022.
Mildenhall Exchange began Stop Sell on 4 May 2021. This exchange will focus on a complete withdrawal of services by December 2022, even if no fibre is available.
Premises serviced by the Mildenhall Exchange will be replaced with SOGEA and SOTAP products and the communication provider will need to provide an over-the-top VoIP replacement service such as a hosted PBX system license or SIP Trunking.
There will be a stop sell point in September 2023, after which PSTN based products will no longer be available for new supply. By December 2025 all PSTN products will need to have been migrated across to replacement Single Order products.
The FTTP Priority Exchange Rollout allows Openreach to transition to alternative products earlier. When FTTP gets to 75% availability within a certain area, Openreach can designate that exchange as a Priority Exchange. At that point, a 12-month notice is given to stop the sale of copper-based products at premises where FTTP is available. If you want a new service or you want to switch suppliers, you will only be able to buy FTTP irrespective of whether you would prefer another service.
Openreach has been rolling out the FTTP Priority Exchange program in tranches, with a new tranche being announced every three months. Currently, there are four tranches, totalling 220 exchanges, which have been designated Priority. The first stop sell of copper-based products happens for 13 of those Priority exchanges in June 2021, with further stop sells in October, January, and April.
In summary, there are two timelines to consider:
This is an ideal opportunity to get ahead of the curve, as many people will only focus on the future 2023 Stop Sell date, while missing on the opportunities that are available today.
Moving forward, Openreach products will be a Single Order (SO) variant of ADSL or Fibre broadband services.
These products will become known as; Fibre To The Premises (FTTP) and Single Order Generic Ethernet Access (SOGEA) which is Openreach’s Broadband only FTTC replacement.
When these Single Order (SO) broadband products are provided there will be no voice on the telephone line and no dial tone, this means the CP will need to provide some form of VOIP service like a Hosted PBX License or Session Initiation Protocol (SIP Trunking) service to provide the voice telephony element which would replace the traditional WLR or ISDN telephone line.
These alternative products fall into two categories:
During the Public Switch Telephone Network closure, all these services need to be tested with new IP technology and the SO products. This means alarm line companies, payment terminals, traffic light systems, payphone lines, emergency pendants, dialysis machines, telemetry devices and any other special service must be tested by the equipment manufacturers. Openreach can provide line test facilities for testing equipment against their individual line configurations.
We strongly suggest that you should engage with your special service supplier at the earliest opportunity to start the conversation about how you protect yourself moving forward.
From September 2023 Openreach will issue a full “Stop Sell” of new supply WLR. When we refer to new WLR there is further clarification needed on what would be considered as a new supply. For example, does this include a transfer to another CP?
As part of the nationwide PSTN, WLR and ISDN Withdrawal, from the end of September 2023 there will be no new line installations for both WLR and ISDN, including conversions of the WLR Line to an ISDN Line, increase of ISDN channels, change of address, start of a stopped line or working line take over.
© rhm telecommunications 2021