If your PSTN migration plan starts with buying a new phone system, you could be missing the bigger picture.
The UK’s Public Switched Telephone Network (PSTN) will be switched off on 31 January 2027, meaning every business still relying on analogue phone lines must move to digital alternatives. However, it’s not just desk phones that are affected. Alarm systems, payment terminals, lift emergency phones, CCTV, access control systems and broadband services may all depend on legacy connections.
The most successful migrations start with a complete business audit, not a new phone system This practical PSTN migration checklist will help you identify every dependency, assign ownership and move to modern communications with minimal disruption.
Step 1: Build a Complete Inventory of Legacy Lines
Start by identifying every analogue line in your business. Record the line number, location, supplier, owner and what each line supports. A line that appears unused could still be connected to a critical business service.
Make sure your audit includes:
- Business phone systems
- Broadband connections
- Fire and intruder alarms
- Lift emergency phones
- Payment terminals
- CCTV systems
- Door entry and access control
- Fax machines
- Any other connected devices
A complete inventory provides the foundation for a successful migration.
Step 2: Bring the Right Departments Together
PSTN migration affects far more than your IT department.
Facilities, finance, operations and security often manage services that rely on analogue lines. Bringing everyone together early helps avoid missed dependencies and unnecessary delays.
Assign one project lead to oversee the migration and ensure every service has a named owner.
Step 3: Confirm the Replacement for Every Service
Every analogue service needs a clear replacement plan.
Some equipment can connect using adaptors, while other devices may require replacement or mobile connectivity. Work with your suppliers to confirm compatibility before making any changes.
Remember, replacing your phone system does not automatically replace every legacy service in your business.
Step 4: Design Your Future Communications
The PSTN switch off is an opportunity to modernise your communications, not simply replace old technology.
Think about what your business will need over the next few years. You may benefit from hosted telephony, Microsoft Teams integration, improved call routing, better reporting, support for hybrid working or a complete Unified Communications as a Service (UCaaS) solution.
Planning ahead now can reduce future costs and improve productivity.
Step 5: Plan the Migration
A well-planned migration reduces risk.
Prioritise safety critical and customer facing services first, then schedule lower priority connections. Allow time for number porting, equipment deliveries, engineer visits and supplier lead times.
Most importantly, never disconnect an existing service until the replacement has been fully installed and tested.
Step 6: Test Everything
Before signing off the project, make sure every service works as expected.
Test:
- Inbound and outbound calls
- Alarm signalling
- Payment terminals
- Lift emergency phones
- CCTV connectivity
- Internet resilience
- Backup connections
Once testing is complete, update your asset register, supplier contacts and business continuity plans so your records remain accurate.
Step 7: Review After Go Live
The project doesn’t end on installation day.
Monitor performance during the first few weeks, gather feedback from users and confirm backup connectivity is working correctly. A post migration review helps identify any remaining issues and ensures every service is performing as expected.
How 4th Platform Supports Your PSTN Migration
Moving away from the PSTN is about protecting your business, not just replacing phone lines.
At 4th Platform, powered by Gamma’s award-winning connectivity and communications solutions, we manage the entire migration process from start to finish, giving you a single trusted partner throughout the project.
Our services include:
- Connected services audits to identify every analogue dependency.
- Business connectivity and UCaaS design.
- Supplier coordination and project management.
- Installation, testing and number porting.
- Ongoing managed support and optimisation.
Whether you’re replacing a single office phone system or migrating multiple sites, we’ll help ensure the transition is smooth, secure and disruption free.
Start Planning Before the Deadline
The 31 January 2027 PSTN switch off is fast approaching, and waiting until the last minute increases the risk of disruption to your business.
The organisations that experience the smoothest transitions are those that plan early, understand every dependency and work with an experienced migration partner.
Book a free PSTN Readiness Assessment with 4th Platform today. We’ll audit your existing services, identify every legacy dependency and create a clear migration roadmap that keeps your business connected today and ready for tomorrow.
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