What is the PSTN switch-off?
The PSTN switch-off is the retirement of the UK’s Public Switched Telephone Network, the copper-based telephony infrastructure that has carried voice traffic in Britain since the 1960s. On 31 January 2027, Openreach will withdraw the last of its PSTN and ISDN services, and every line that has not migrated to a digital alternative will stop working.
It’s easy to underestimate just how significant this migration is. It touches every business with a landline. It touches every alarm and lift line. It touches every payment terminal on a legacy analogue feed, every telecare pendant relying on an analogue socket and every operator carrying voice traffic over TDM. It also touches every rack of legacy switching equipment in every UK exchange, and that side of the story gets almost no coverage in the general commentary.
At DTC we buy, refurbish, redeploy and responsibly retire the PSTN hardware that networks are pulling out. In this guide we’re going to dive deep into the migration side, as well as what actually happens to the kit as it comes off the wall, and how we can help you recover costs by responsibly redeploying and recycling your legacy PSTN equipment.
Retiring PSTN, ISDN or WLR equipment? DTC handles the kit
For over 30 years we’ve helped UK operators, altnets and enterprises recover value from decommissioned telecom hardware. Buyback, redeployment and AATF-certified destruction, and everything the migration team leaves behind.
Why is this happening?
There are three primary reasons driving the PSTN switch-off.
The equipment is EOSL
The switching platforms in UK telephone exchanges (Alcatel 1000 E10, Marconi UXD5, Ericsson AXE, Nortel DMS-100, Siemens EWSD) were largely designed and installed in the ’80s and ’90s. The OEMs have long since stopped manufacturing spares. Engineering skills for these platforms are also retiring with the workforce that installed them. Fault rates on the legacy platforms have been rising materially year-on-year, as tracked in Ofcom’s Openreach monitoring reports. Put simply, the equipment is old and unreliable and pretty soon there’ll be very few people with the engineering skill to reliably repair it.
The economics don’t support continuing to run the PSTN network
Maintaining a copper voice network in parallel with a data network costs Openreach double what a single all-IP network would cost. Every developed-market operator has run the same numbers on parallel-network cost and reached the same conclusion. The UK is actually a very late mover in this. Germany, the Netherlands, Estonia and Japan have already completed their switch-offs.
Regulatory considerations
Ofcom’s Wholesale Local Access framework has progressively favoured fibre. Retiring PSTN removes the last practical reason for Openreach to maintain WLR as a discrete regulated product, which in turn removes a substantial operational and regulatory cost.
The timeline to PSTN switch-off
These dates have been set by Openreach, and at this point they’re unlikely to be changed.
What is being switched off?
There is actually quite a lot of confusion in the market about what exactly is being switched off.
PSTN
Every analogue voice product runs on the PSTN, so every analogue voice product is being retired. That includes standard analogue exchange lines, WLR2 and WLR3 wholesale lines, and analogue voice as an add-on to broadband. All end on 31 January 2027. The physical copper will stay and will need to be recovered. The service delivered over it does not.
ISDN2 and ISDN30
ISDN2 (Basic Rate Interface) and ISDN30 (Primary Rate Interface, thirty 64 kbps B channels on a single E1) are being withdrawn on the same date. The ISDN switch-off is the harder of the two migrations in practice, because it involves reconfiguration of PBX hardware, review of dial plans, and usually replacement of on-premise voice infrastructure, which DTC can help you with.
WLR
WLR (Wholesale Line Rental) is the wholesale mechanism by which non-BT communications providers rent the last-mile copper voice line from Openreach and resell it. When the PSTN retires, WLR retires with it. The WLR withdrawal completes on 31 January 2027. FTTC broadband delivered over WLR migrates to SoGEA, which uses the same physical connection without the voice channel.
Who is affected?
Businesses and industrial systems
Businesses with a live analogue or ISDN estate should treat 31 January 2027 as a hard operational deadline. Below the obvious voice-line replacement question sit harder ones. Every alarm dialler, lift line, chip-and-pin terminal, building management system, industrial SCADA link, franking machine, EPOS or door-entry system that reports over an analogue channel will stop working on 1 February 2027.
Watch out. The most common failure mode we see is a business that has migrated its phones to hosted VoIP but has left an alarm or a lift line quietly running on a WLR service that will stop working pretty soon.
Vulnerable users and telecare
Vulnerable users are the most sensitive category in this migration. Ofcom’s General Conditions require providers to identify at-risk customers and take specific steps before migration, including a minimum of one hour of emergency access during a power outage, free of charge. The Telecare Action Board, established in January 2024, sets the national framework for how telecare devices are identified, tested and swapped where necessary. Analogue telecare pendants must be replaced with a digital-native unit or served by an analogue-to-IP converter that has been tested against the specific device. Compatibility is not universal.
Migration options
There is no single replacement for PSTN. There are three families, and the right combination depends on the site.
SIP trunks are the direct replacement for ISDN30. A SIP trunk carries voice as IP packets to a SIP provider, using the existing PBX. Most enterprise PBX platforms (Cisco Unified Communications Manager, Avaya Aura, Mitel MX-One, 3CX) have supported SIP trunking natively for years. When the ISDN30 goes, the PRI cards in the PBX, the E1 test kit in the comms room and the media gateways at the network edge all come off the wall. We buy that material back through our network spares purchasing programme where it retains value.
Hosted VoIP moves the PBX function itself into the provider’s data centre and delivers voice as a subscription. It suits businesses that do not want to maintain their own PBX, or that are replacing an ISDN service where the on-premise equipment has itself reached end-of-life. When hosted VoIP replaces an on-premise PBX, the retired chassis and handsets are a disposal problem the day the new service goes live. Our asset management service is designed to catch this transition and recover value from it before the equipment starts costing rather than earning.
Underlying access is either SoGEA (FTTC without the voice channel), FTTP (Openreach is committed to 25 million premises by end of 2026), or a business-grade Ethernet leased line where voice performance can’t be compromised.
Retiring PBX chassis, PRI cards or media gateways as part of your migration? Get a buyback valuation from DTC
What happens to the retired kit?
This is the part of the story that gets almost no attention in the general commentary, but it matters a great deal. Every exchange consolidation, every ISDN30 migration and every WLR customer disconnection leaves physical equipment stranded. That equipment is either an asset, a liability or an e-waste problem depending on how it is handled.
At DTC, we’ve got over 30 years of running reverse logistics programmes for operators, and it tells us the same thing repeatedly. Operators that plan equipment retirement early recover meaningful value. Operators that leave it to the end of the migration recover almost nothing. The equipment loses value in three ways during the delay: physically (dust, damp, damage), commercially (buyers move on to alternative sources), and administratively (audit trails go cold, provenance is lost, serial numbers become unverifiable).
Auditing your estate
The first job is knowing what you actually have. In practice, the asset register for a large PSTN operator is often years out of date, and the physical audit that reveals what is actually on the rack (down to card revision, serial number and installed capacity) is usually the point at which real planning starts. A DTC equipment recovery engagement typically starts with a joint audit like this.
Buyback and resale
Legacy telecom equipment retains real commercial value on the secondary market. The two markets that consistently pay for it are operators with parallel installed bases keeping their own kit running, and developing markets where end-of-life Western equipment is still deployed as new-in-service infrastructure. The categories that command the strongest resale values in our experience are optical transmission cards (Ciena, Infinera, Nokia, Adva), access equipment (Huawei MA5600T, ZTE C300, Alcatel-Lucent 7360 ISAM), legacy TDM switching cards (Ericsson AXE, Alcatel 1000 E10), PRI and BRI cards from Cisco, Avaya and Mitel, and optical transceivers of every generation. Put simply, your equipment might be old and end-of-life, but that doesn’t mean it won’t be valuable to a secondary or tertiary-market operator where legacy equipment is still very much in use.
Secure destruction and WEEE compliance
Not every retiring platform has resale value. Older exchange gear, damaged units, and equipment carrying data on non-removable storage may need to be destroyed rather than sold on. In the UK this is a regulated activity under the WEEE Regulations, and where the equipment held customer or configuration data, under UK GDPR too. DTC operates as an Approved Authorised Treatment Facility (AATF) and issues serialised destruction certificates. For enterprise or CNI operators subject to internal or regulator-driven audit, the documentation trail is the difference between a compliant retirement and an incomplete one. Our network equipment recycling service exists to close out exactly that loop.
The specific vendor landscape being retired includes Alcatel 1000 E10, Marconi UXD5, Ericsson AXE, Nortel DMS-100, Siemens EWSD and Lucent 5ESS voice switching, plus Alcatel-Lucent 7302 and 7330 ISAMs, Huawei MA5600 series, and ZTE ZXA10 access. Cards from these platforms retain international resale value where a live installed base still exists. Complete chassis, in most cases, do not.
Get an audit and buyback quote from DTC
Every DTC engagement starts with a joint equipment audit. We’ll value what’s coming off the wall, route the resaleable material back into supply, and issue AATF-certified destruction certificates for anything that has to go.
Preparing your business or network for switch-off
For businesses and altnets with material PSTN or ISDN exposure, this is what you must do before 31 January 2027.
- Complete a line-level audit. Every voice line, every ISDN channel, every device connected to a line. Owner assigned per line.
- Identify hidden analogue services. Alarms, lifts, EPS meters, SCADA back-haul, telecare, franking machines, door-entry.
- Choose a migration path per line: SIP trunk, hosted VoIP, native digital service, mobile-only, or interim ATA.
- Confirm underlying access: SoGEA, FTTP, or leased line.
- Test devices against their replacement path. Especially for alarms and telecare.
- Plan number porting. Timescales tighten as the switch-off date approaches.
- Schedule vulnerable-user migrations first, with in-order support where needed.
- Plan the equipment retirement in parallel. Route it to buyback, redeployment or WEEE-compliant destruction before the migration team moves on.
Need help with step 8? DTC handles the equipment retirement side end-to-end. Talk to our reverse logistics team