The deadline is close: the UK’s Public Switched Telephone Network (PSTN) is due to switch off on 31 January 2027. Openreach says the date is final and will not be extended. With roughly three and a half months to go, SMEs still relying on analogue or ISDN services need to move from awareness to an agreed, tested migration plan.
This is not simply a matter of replacing desk phones. Lines may support alarms, lift phones, payment terminals, broadband, door entry, fax machines and out-of-hours contact numbers. If these dependencies are missed, a phone-system change can become a business-continuity problem.
The strategic question is not just “Which digital phone system should we buy?” It is “How should voice, connectivity and support work together for this business?”
Start with the strategy, not the handset
Through the Fractal IT Director approach, David leads the consultation: establishing the risks, dependencies, roadmap and cost decisions before implementation begins. The aim is to make voice part of the wider IT plan, alongside security, hybrid working, continuity and future growth.
That matters because a cloud phone system depends on a functioning network, suitable user access and clear support arrangements, and the same planning applies to Cloud Solutions elsewhere in the business. Managed IT Services and Voice and Connectivity can then act as execution services that put the agreed strategy into practice. They are not a substitute for it.
Openreach’s Big Switch Off guidance and the Government’s guidance on moving landlines to digital technologies both urge businesses to check connected equipment and arrange migration with their communications provider. Do not assume a business will have a suitable emergency fallback if it misses the deadline. Any limited continuity arrangement is not a designed migration plan.
1. Audit every line and device
Begin with an inventory, not a supplier quote. Record every analogue, WLR and ISDN line, including lines that nobody thinks of as “the phone”. Check bills, provider portals, wiring cupboards, alarm contracts and equipment records. Ask each provider to confirm what service is supplied, what it supports and when it must be migrated.
Include:
- Desk phones, reception lines, fax machines and out-of-hours numbers
- Business broadband that relies on copper services
- Intruder and fire alarms, CCTV and monitoring systems
- Lift and emergency phones
- Payment terminals, door entry and intercoms
- Lines used for modems, remote access or other specialist equipment
Ask the supplier of each connected device whether it is compatible with the proposed digital service. Some equipment may need reconfiguration, a cellular connection or replacement. A device that appears to work during a short test may still fail to report correctly to its monitoring centre, so arrange proper end-to-end testing.
2. Design the digital voice service around the business
Digital voice, often delivered as VoIP or All-IP, can support flexible calling, but the design needs to match how staff actually work. Confirm the number of users and devices, then plan call routing, queues, ring groups, reception cover, voicemail and out-of-hours handling.
Check how pricing works. Cloud voice is commonly licensed per user, and features or call recording may carry additional costs. A cost comparison should consider the complete service, not simply the headline price per extension.
Plan for mobile and home-working users, too. Decide how they will make and receive calls, what caller ID they will present, and how access will be managed if a device is lost or a staff member leaves. Confirm that the numbers you need can be ported, who coordinates the port and how legacy extensions, analogue handsets or specialist adaptors will be handled.
Most importantly, ask what happens when the internet connection fails. Call diversion to mobiles, a secondary connection or alternative arrangements may help, but each option must be configured and tested. “It should fail over” is not a test result.
3. Make connectivity resilient enough for voice
Putting cloud voice on an untested single circuit creates a single point of failure. If that circuit goes down, calls may go with it, even if the phone platform itself is healthy.
Review whether full-fibre business broadband is available and suitable for each site. Where continuity matters, consider a separate backup circuit or 4G/5G failover. A backup should not just exist on a diagram: test the switchover and confirm that it can carry the traffic and services the business needs.
A Network Solutions review should also cover firewall rules, VLAN configuration, Wi-Fi and network capacity. Placing voice on its own VLAN can help prioritise calls over general traffic, but correct configuration and monitoring are essential. For critical sites, resilience should reflect the impact of downtime, not a generic package applied everywhere.
Include power in the design. Routers, fibre equipment, firewalls, switches and handsets may stop working during a power cut. Assess battery backup, an uninterruptible power supply and mobile alternatives where appropriate, then document what staff should do.
4. Treat telephony as a cloud workload
Moving voice to the cloud changes more than the connection. Staff accounts need appropriate access controls and multi-factor authentication. Leavers’ accounts must be removed promptly, and administrators should know who can change routing, recordings and user permissions.
If calls are recorded, establish why, which calls are recorded, who can listen, how recordings are protected and how long they are retained. Confirm that the chosen settings fit the organisation’s policies and applicable obligations.
Use the migration to review total cost. Technology Expense Management (TEM) can identify overlapping line rentals, unused numbers, redundant contracts and cloud licences that are no longer needed. Compare current and future costs, including broadband, mobile failover, call features, recording, equipment and support. Review the position again after migration: duplicate services have a habit of surviving long after the need for them has disappeared.
For businesses with a wider modernisation programme, a Dynamics 365 Jump Start discussion can help place telephony changes into a broader cloud and operational roadmap. The right sequence depends on business priorities, not on a sales calendar.
5. Give staff one clear route to support
After cutover, staff need to know where to report a failed handset, poor call quality or lost connectivity. Helpdesk Support should provide one clear route to log and categorise these faults, even where different suppliers ultimately resolve them.
Track repeat issues, response times, escalations and recurring site problems. That evidence helps distinguish a one-off fault from a service pattern, and gives the business a firmer basis for holding providers to agreed service levels. It also makes the support experience clearer for staff: one route in, rather than a tour of supplier phone menus.
Where an SME relies on an IBM i platform, include its connectivity, remote support access and dependent services in the change review. IBM i Management is a specialist consideration, not a reason to treat voice migration as a separate island.
A practical timeline to 31 January 2027
Now: Assign an owner, gather bills and contracts, inventory every line and connected device, and ask providers to confirm migration requirements.
Next: Agree the voice and connectivity design. Confirm number portability, equipment compatibility, broadband availability, failover, security and costs. Book any engineering work early; providers’ engineering capacity may tighten as the deadline approaches.
Before cutover: Configure the new service and test inbound and outbound calls, queues, ring groups, voicemail, emergency calling arrangements, number presentation and failover. Test alarms, payment systems, lift phones and door entry with the relevant suppliers.
After cutover: Get staff feedback, resolve faults through the agreed helpdesk route, check invoices for duplicate services and retain evidence of testing. Do not cancel legacy lines until the replacement and dependent equipment have been verified.
Questions to ask before you sign
- Which lines and devices are included in the migration, and which are not?
- Who owns number porting, device checks and end-to-end testing?
- What happens to calls during a broadband or power outage, and has that been tested?
- What are the full recurring and one-off costs, including licences, recording and backup connectivity?
- Who takes the first fault report, and how are provider escalations measured?
- What must be completed before legacy services are cancelled?
The 31 January 2027 deadline leaves little room for an untested last-minute change. A focused audit and a consultancy-led plan can turn the switch-off into a controlled redesign of voice, connectivity and support, not a scramble to reconnect the phones.
For broader information about Evestaff’s group of services, visit evestaff.co.uk.
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