PSTN Switch-Off UK 2026: Helpdesk Readiness for All-IP

A practical, year-aware UK helpdesk checklist for preparing users ahead of the 2027 PSTN to All-IP switch-off. Includes day-to-day actions, owner responsibilities, and practical steps.

June 5, 2026

PSTN to All‑IP: your 2026 UK helpdesk game plan

The PSTN is being retired in the UK with organisations moving to All‑IP by January 2027. That makes 2026 the decisive year for tidy execution rather than last‑minute scrambling. This PSTN switch-off checklist UK 2026 sets out clear, day‑to‑day helpdesk actions so you can brief users, map affected lines, replace legacy kit and prove voice resilience before the switch‑off.

We focus on practical helpdesk work: line and device inventories, who owns what, router/ONT swaps, VoIP testing, call‑quality tuning, number porting, and power/failover plans. You’ll also get a simple communications schedule and testing approach that fits SME and public‑sector realities.

By the end, you’ll know exactly which steps to take in 2026, how to handle tricky dependencies like alarms, lifts and payment terminals, and how to prevent user‑visible issues during change. The aim is calm execution, fewer surprises, and a smooth transition to All‑IP.

PSTN switch-off checklist UK 2026: what to do now

Key point: The move to All‑IP touches more than desk phones. Anything that dials or relies on analogue lines—fax, PDQ/card machines, care/Redcare alarms, lift lines, door entry, telemetry—must be identified and given an IP‑ready plan.

1) Build a complete line and device inventory

Export all phone numbers and circuits from billing and config tools; match each to a location, socket and device.
Walk critical sites to spot “hidden” lines: comms cupboards, lifts, plant rooms, entry systems, security panels, meters.
Label ownership per item (Helpdesk, Facilities/Estates, Security, Finance, Vendor) to avoid gaps.
Capture dependencies: power requirements, network ports, SIMs, analogue adaptors, and any vendor support contracts.

2) Map each PSTN‑dependent device to an All‑IP action

PSTN‑dependent item	Typical 2026 action	Likely owner
Desk/cordless analogue phones	Move to hosted VoIP or IP‑PBX; use IP phones or softphones; ATA only if interim	Helpdesk / Telecoms
PDQ/card machines	Swap to IP or 4G terminal; confirm acquirer support and test transactions	Finance / Vendor
Fax	Retire, or use secure e‑fax service; if essential, validate T.38 or agreed alternative	Info Governance / Helpdesk
Alarms (intruder/fire/care/Redcare)	Request vendor IP/cellular module; coordinate certification testing	Facilities / Security / Vendor
Lift emergency lines	Vendor upgrade to IP/cellular solution and compliance sign‑off	Estates / Lift Vendor
Door/entry/intercom	Replace with SIP/IP‑enabled unit; confirm network PoE and VLAN plan	Facilities / Helpdesk

Tip: Analogue telephone adaptors (ATAs) can bridge gaps, but treat them as temporary. They add failure points and may not support tones, alarms or fax reliably.

3) Connectivity and LAN readiness for VoIP

Access: Prefer FTTP or business‑grade broadband; where unavailable, use the most stable option and plan 4G/5G failover.
Router: Confirm SIP provider compatibility; review SIP ALG behaviour and disable if your provider recommends.
Quality: Apply QoS for voice, consider a voice VLAN, and verify upstream/downstream shaping during busy hours.
Power: Add a UPS for ONT and router; if using IP phones/PoE switches, include them in the power plan.
Firewall: Allow required signalling/media ranges from your VoIP provider; restrict everything else.
Wi‑Fi: If using softphones, validate roaming and 5 GHz coverage in meeting areas to avoid call drops.

If your team needs a structured refresher on routing, switching and QoS fundamentals, the CompTIA Network+ route is a solid fit for helpdesk and junior networking roles.

4) Numbering, porting and calling plan

Decide which numbers to keep, retire or merge; align with departments and locations.
Start porting early—build in lead time for approvals, losing/winning provider coordination and test windows.
Design the call flow: auto‑attendant, time‑of‑day routing, queues, hunt groups, overflow and voicemail policies.
Document emergency calling and location details per site; clearly brief users about behaviour during power cuts.
Pilot with a non‑critical number first, then roll out in waves with rollback points.

5) User communications and support playbook

What to tell users

What is changing, when, and what stays the same (phone numbers, headsets, apps).
How to place/transfer/park calls, join meetings, set voicemail and update caller ID location if required.
What to do in a power or internet outage, and who to contact.

Helpdesk readiness

Publish short how‑tos, call‑quality triage scripts and a known‑issues list in your KB.
Capture device swaps and serials in tickets to maintain traceability.
Arrange floor‑walking support on go‑live days.

For structuring tickets and knowledge base articles, see our guide on job‑ready helpdesk documentation.

6) Test scenarios and resilience checks

Voice quality: Test inbound/outbound, transfers, conference joins and call recording where in use.
DTMF: Verify IVR input works end‑to‑end (auto‑attendants, banking lines, vendor portals).
Softphone: Check sign‑in policies, device switching, roaming on Wi‑Fi and headset firmware.
Non‑voice devices: Run vendor‑witnessed tests for alarms, lifts and entry systems after upgrade.
Failover: Simulate WAN loss to confirm 4G/5G backup and call‑routing behaviour.
Power: Prove UPS runtime for ONT, router and PoE switch; document safe shutdown steps.

Caution: Do not place test calls to emergency services. Instead, confirm emergency address details with your provider, brief users about power‑cut behaviour, and ensure signage is visible where required.

7) Your 2026 rollout timeline

Q1–Q2 2026

Complete inventory and ownership mapping; raise vendor tickets for alarms/lifts.
Select VoIP platform and connectivity; order any FTTP/routers/PoE switches/UPS.
Pilot a small group, fix QoS and softphone issues, finalise call flows.

Q3–Q4 2026

Stage number porting in waves; run user briefings one week before each cutover.
Swap analogue endpoints; retire or replace faxes and PDQs; validate vendor sign‑off.
Run resilience tests; update diagrams, asset lists and KB; close decommission tickets.

8) Common pitfalls to avoid

Leaving number porting until the last minute.
Forgetting non‑voice devices (lifts, alarms, entry, telemetry).
Relying on ATAs for complex use cases like alarms or fax without vendor approval.
No power plan for ONT/router/PoE—phones go down during outages.
Skipping QoS and Wi‑Fi validation for softphones.
Insufficient user comms and floor‑walking on go‑live days.

9) Roles and ownership

Helpdesk owns

Inventory, user comms, ticketing and knowledge base.
Softphone rollouts, headsets, basic QoS checks and first‑line call testing.
Coordination with providers during porting and migration windows.

Coordinate with

Facilities/Estates for lifts, alarms and entry systems.
Security/Fire vendors for certified module upgrades and witnessed tests.
Finance for PDQ/card machine replacements and merchant acquirer approvals.

Final advice: Treat 2026 as your controlled run‑up: finish the inventory, lock in vendor upgrades, port numbers in waves, and prove power and failover. Keep users informed, keep tickets tidy and measure twice before each cutover. Book a free consultation to get personalised advice on the right IT course or career path for your goals.

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