PSTN Migration Checklist for Businesses

An operational readiness page for auditing lines, dependencies, owners, testing and cutover preparation

Use this checklist to prepare your business for the PSTN switch-off by auditing every line, reviewing connected services, assigning internal owners, checking continuity risks, and making sure your migration work starts from a complete operational picture.

Strategic planning graphic for the UK PSTN switch-off in 2027, featuring readiness routing and business continuity safeguards for VoIP migration.

Preparation first

Map your lines, devices, owners and testing tasks before you move into live migration planning.

What this checklist is for

This page is for operational preparation. It helps you document dependencies, reduce continuity risk, and confirm what must be reviewed before cutover.

  • Audit lines, sites and live services
  • Review connected devices and hidden dependencies
  • Assign owners, testing tasks and cutover responsibilities
Interactive VoIP recommendation tool for UK businesses, providing tailored provider shortlists based on headcount, budget, and PSTN readiness.

Shortlist digital options

Detailed timeline and guidance for the UK PSTN to VoIP migration, highlighting routing for business continuity and risk mitigation.

Follow the migration process

Strategic planning graphic for the UK PSTN switch-off in 2027, featuring readiness routing and business continuity safeguards for VoIP migration.

Review switch-off readiness

Core readiness checklist

Work through these checkpoints in order so you do not miss line-dependent services, internal responsibilities, or cutover risks.

1. Audit every line and site

List every location, live line, service type, supplier, circuit reference and business use so hidden legacy services do not get missed.

2. Review connected devices

Check alarms, lift lines, payment devices, CCTV, fax, access systems and any service that may still depend on a legacy line.

Keep going

3. Separate critical from non-critical

Prioritise services that affect safety, payments, compliance, access, emergency contact or operational continuity so planning effort stays focused on real risk.

What you should review next

Once the basic audit is complete, move into the deeper operational reviews below so nothing important is left undocumented.

Number inventory

Document main numbers, DDIs, hunt groups, fax numbers, published lines and any number that must be retained during migration.

Owners and suppliers

Assign one accountable internal owner and one supplier contact for every critical dependency so no service is left without a decision-maker.

Testing and cutover

Prepare validation steps for inbound calling, outbound calling, routing, voicemail, emergency paths, fallback arrangements and post-cutover sign-off.

Checklist questions every business should answer

These questions help turn a basic inventory into an actionable preparation plan that supports migration, testing and continuity.

  • Which live services still rely on PSTN, ISDN or line-dependent broadband?
  • Which devices or services would create the highest operational risk if they failed?
  • Who owns each dependency internally, and which supplier supports it externally?
  • What must be tested before cutover, during cutover, and immediately after go-live?
Strategic planning graphic for the UK PSTN switch-off in 2027, featuring readiness routing and business continuity safeguards for VoIP migration.
Detailed timeline and guidance for the UK PSTN to VoIP migration, highlighting routing for business continuity and risk mitigation.

Preparation areas to complete before go-live

Use these operational workstreams to confirm whether your business is actually ready to move from preparation into execution.

Broadband and resilience

Check connectivity assumptions, line-dependent broadband, router resilience and whether key sites need backup or fallback options.

Power and continuity

Review what happens during a power cut, which sites need backup arrangements, and how emergency or critical calling will still be handled.

Final checks

Cutover readiness review

Do not move into execution until your inventory, suppliers, owners, test plan, fallback path and sign-off criteria are documented clearly.

Quick readiness summary

Before you move on, make sure these essentials are in place across the business.

Inventory complete

Sites, services, numbers, devices and dependency owners are all documented in one working list.

Testing ready

Validation steps, fallback routes, supplier contacts and sign-off criteria are defined before live migration begins.

Ready to act

Once the checklist is complete, move straight into provider shortlisting and migration sequencing with less guesswork and fewer surprises.

Next step

Move from checklist to action when the basics are complete

When your audit, owners, dependencies and testing plan are documented properly, you are ready to move into provider shortlisting and migration sequencing with far more control.