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PSTN Replacement Services for UK Organisations

The UK’s PSTN/ISDN networks are being withdrawn. Analogue voice, ISDN2/ISDN30 and many copper‑based broadband and device lines will cease. We help businesses, charities and multi‑site organisations audit, plan and migrate to All‑IP alternatives with resilience built‑in.

What Is PSTN Replacement?

PSTN replacement is the process of moving services away from the UK’s old copper phone network (PSTN and ISDN) to modern digital, All‑IP alternatives. BT are planning for the legacy network to be fully switched off by 31 January 2027, meaning any service that relies on analogue lines — including phone lines, ISDN, ADSL/FTTC broadband, lift lines, alarms and other connected devices — must migrate to digital replacements such as VoIP, SIP, FTTP/SoGEA, 4G/5G, and IP‑based signalling.

PSTN replacement ensures continued operation, improved reliability, modern features, and long‑term support as the UK moves to a full fibre and All‑IP future.

What’s Changing and When

Openreach is retiring the Public Switched Telephone Network (PSTN) and ISDN. Nationwide stop‑sell of new copper services is in place, exchange withdrawals are progressing, and the final switch‑off deadline is 31 January 2027 (per your blog content). Once an area completes migration, copper‑dependent services will stop.

Why move now?
  • Avoid forced “emergency” migration and downtime as exchanges withdraw service.
  • Consolidate lines, reduce cost/complexity, and improve reliability.
  • Unlock modern features (VoIP/Teams, monitoring, APIs, analytics).

What’s Affected

More Than Just Phones

Many services still depend on PSTN/analogue lines:

Communications

  • PSTN voice lines, ISDN2e/ISDN30
  • Fax & PDQ/card terminals
  • Door entry & intercoms
  • Lone‑worker/emergency phones

Connectivity

  • ADSL, FTTC and other copper broadband
  • Legacy routers tied to PSTN

Critical & Safety Systems

  • Lift emergency phones
  • Fire/intruder/telecare alarms
  • Building management & telemetry
  • Roadside/SOS help points, gate/barrier access

If these are not migrated, they will simply stop working after switch‑off, creating operational and safety risks.

Have You Checked?

  • Chip & PIN payment machines
  • CCTV systems
  • Door entry systems
  • Electronic tills
  • Medical emergency phones
  • EV charging stations
  • External door/entry bells
  • School security devices
  • Fax machines
  • Fire alarms
  • Franking machines
  • Intruder alarms
  • Lift alarms and lift emergency phones
  • Printers with fax/analogue modules
  • Telecare devices
  • Vending machines
 
Download printable checklist to help you audit every device that could be affected.
Download the PSTN Checklist PDF

Why It Matters

Risk & Compliance

  • Continuity: Safety‑critical lines must operate through power/ISP outages.
  • Compliance & insurance: Alarm signalling must remain reliable to meet policy and life‑safety requirements.
  • Operations: Payments, entry systems and remote monitoring must remain online.
  • Cost & simplicity: Modernising lets you rationalise lines, carriers and bills.

How Spectrum Helps

1) Audit & Discovery

We catalogue every PSTN‑dependent device (including “hidden” lines in lifts, panels, gates, comms rooms).

Deliverable: Line & Device Inventory + Risk Map

2) Design & Options

Per‑service replacement design (voice, broadband, critical systems).

Deliverable: Migration Design (SIP/Hosted, FTTP/SoGEA/Ethernet, LTE backup, UPS plan)

3) Pilot & Prove

Prove signalling and resilience (power failure, ISP failure, SIM failover).

Deliverable: Pilot Sign‑off & acceptance results

4) Rollout & Numbering

Coordinated installs, number porting, gateway deployment, documentation.

Deliverable: Site‑by‑Site Migration Plan and change window

5) Monitoring & Support

24/7 monitoring options for critical paths; UK support for incidents, updates and changes.

Deliverable: Ongoing Reporting & Support SLAs

Speak to a Specialist

Replacement Options

Your Digital Alternatives

Voice & PBX

  • SIP Trunking (for existing PBXs)
  • Digital single‑line replacements for small installs
  • Number porting/virtualisation to keep all DIDs

Voice & PBX

  • FTTP for gigabit performance (where available)
  • SoGEA/SOADSL (single‑order broadband without a phone line)
  • 5G/4G primary or failover access (dual‑path resilience)
  • Managed routers with monitoring and alerts

Voice & PBX

  • Digital Lift Lines (ATA/ISDN‑TA + LTE backup + UPS)
  • IP Alarm Signalling (fire/intruder/telecare), multi‑port gateways (1–48)
  • Emergency/Help Points with ruggedised routing and remote monitoring
  • ATA/ISDN‑TA for legacy controllers and PBXs
  • Remote health checks for line status and signalling

SIP‑agnostic by design

Keep your existing SIP/hosted voice provider, or choose Spectrum SIP for single‑ownership and optimised behaviour in low‑traffic, critical environments (emergency routing, NAT‑resilient registrations, HA routing, end‑to‑end failover testing).
Communications Services

Quick Decision Table

Existing PSTN/ISDN ServiceRecommended Replacement
PSTN voice lineHosted VoIP / Teams Phone / Digital single‑line
ISDN2e / ISDN30SIP Trunks (or migrate to Hosted/Teams)
ADSL / FTTCFTTP or SoGEA (5G/dual‑path failover optional)
Lift emergency phoneATA/ISDN‑TA + LTE backup + UPS + monitoring
Fire / intruder / telecare alarmsIP alarm signalling via ATA/gateway + 4G failover
Door entry / intercomIP intercom or ATA + resilient router
PDQ / legacy faxIP‑enabled terminals or inbound fax‑to‑email
SOS/help points, barriers & gatesRugged router + monitored 4G/5G or dual‑path WAN
Request a Free PSTN Audit

On-Premises Phone Systems & Hybrid Solutions

If cloud isn’t right for your entire organisation, we support:

  • On‑premises PBX systems
  • Hybrid configurations combining PBX + cloud services
  • Prem‑as‑a‑Service models
  • SIP Trunking to modernise legacy PBXs

Our hybrid approach ensures you can transition at the pace that suits your business.

Industries We Support

Charities & care providers · Theatres & cultural venues · Education · Multi‑site SMEs · Hospitality & leisure · Logistics & manufacturing · Local government & estates
Case Studies

Frequently Asked Questions

Openreach is retiring the PSTN/ISDN networks. New copper services are stop‑sold and the final deadline is 31 January 2027. After withdrawal in your area, copper‑dependent services will stop.
Not on PSTN. These require engineered digital alternatives with resilience (e.g., ATA/ISDN‑TA, LTE failover, UPS, monitored health checks). We specialise in safety‑critical replacements.
Yes—number porting and virtualisation are part of the migration. We’ll retain DIDs and set correct routing for Hosted/SIP/Teams.
No. Our solutions are SIP‑agnostic and work with your current provider. Choosing Spectrum SIP gives single‑ownership of the whole stack and optimised behaviour for critical systems.
Move to FTTP or SoGEA. Where fibre isn’t available today, we’ll use SOADSL or 5G as interim/backup.

A reliable business internet connection is essential. Spectrum can assess your current connectivity and recommend improvements such as FTTP, Ethernet or leased lines if needed.

Often less overall once lines are consolidated. We can provide Device‑as‑a‑Service for gateways/routers/UPS to reduce CAPEX.
Single sites can be fast; complex estates need planning, pilots and staged cutovers. The sooner we audit, the smoother it runs.

FAQ

Stilll have questions?

Speak to a Specialist on 01283 749 990 or drop your details into our contact form – we’re happy to help.

Ready to replace PSTN safely?

Request a free audit. We’ll identify every copper‑dependent service, design the right All‑IP replacements and manage a smooth, resilient migration.
Client feedback
5 stars for superfast service.
The Pioneer Group
I love Spectrum they always do what they say
Royal Institute of Chartered Surveyors
Awesome World class customer service from Spectrum and Chloe as usual
Checkland Kindleysides
Super helpful and quick - my work phone got stolen and the team was able to issue a replacement immediately + were super helpful with follow up questions.
Warner Brothers
Spectrum very efficient in providing services. Response to emails is sooo quick and they always give good advice to issues.
Keep it up
University of Bristol
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Spectrum was created with the aim of providing clients with cost effective solutions for communication services, supported by exceptional account management. 

Spectrum’s highly skilled and experienced team is focused on keeping at the forefront of telecoms technology including product differentiation and market leadership.

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