The 2027 PSTN switch-off is no longer a far-off date. Openreach has been steadily switching off the legacy copper network across the UK, and any business still using analogue phone lines, ISDN, or DSL-based broadband will need to migrate before their exchange is closed. For UK SMEs, this is not just a phone-system change — it touches alarm panels, lift lines, card terminals, fax machines, EPOS, door entry, and dozens of other devices that quietly rely on a copper line.

This guide explains exactly what hosted IP communications are, what the switch-off means in practical terms, and how Omni Telecom's IP Communications service handles the entire migration so business owners and IT managers can stop worrying about it.

What "IP Communications" actually means

IP Communications is the umbrella term for any voice or unified-communications service delivered over an IP network rather than the legacy PSTN. In practice, that covers four overlapping technologies:

  • Hosted VoIP / Cloud PBX — your phone system runs in a data centre, not in a cabinet on your wall. Handsets, softphones and mobile apps register over the internet to a multi-tenant platform.
  • SIP trunking — replaces ISDN30 lines for sites that still want to keep an on-premise PBX. Cheaper, more flexible, and ready for future expansion.
  • Mobile twinning and softphone — your desk extension rings on your mobile, your laptop, or both. One number, follows you anywhere.
  • Unified communications (UC) — voice plus video, messaging, presence and contact-centre features in a single application, usually integrated with Microsoft 365.

The right mix for a given business depends on size, sector, existing infrastructure, and how much remote working is already in place. A 12-person accountancy practice usually wants pure hosted VoIP with mobile twinning. A 60-bed care home may need SIP trunks plus emergency lines. A multi-site retailer wants a combination of hosted VoIP for staff and dedicated PSTN-replacement lines for EPOS and lift comms.

What the 2027 PSTN switch-off means in practice

The Openreach programme is removing the analogue phone network — Wholesale Line Rental (WLR) — across the UK. The process began in 2021 and runs through to early 2027. Around 14 million premises rely on a copper line for at least one device, and each affected business has to migrate before its local exchange "stop sells" and then "withdraws". For UK SMEs, the practical consequences are:

  • If you have a traditional phone system (analogue or ISDN), it stops working when the line is decommissioned.
  • Anything that quietly uses a phone line — a lift autodialler, an alarm signalling device, a fax machine, a card terminal — will also stop working unless it is moved to an IP equivalent.
  • Your broadband may be affected too. ADSL and FTTC products that ride on the copper pair are being replaced by FTTP (full-fibre) or SoGEA. If your existing broadband is on a copper-dependent product, the same exchange withdrawal removes it.
  • Devices that need a working line during a power cut (lifts, intruder alarms with monitored signalling, security door comms) need either a 4G/5G fallback, a battery-backed router, or a dedicated PSTN-replacement line.

The most common mistake we see is businesses focusing on the desk phones — and forgetting the alarm panel, the lift, and the EPOS printer. By the time the line is cut, those secondary devices have to be migrated under time pressure, often at a premium.

What UK SMEs need to do

The migration breaks down into four steps. Most businesses can complete the audit and procurement in 2–4 weeks; the cutover itself takes a single day per site.

1. Run a full connected-device audit

List every device in the business that uses a phone line — including the ones nobody talks about. Lifts, alarm panels, card terminals, door-entry comms, fax machines, fire-monitoring, telecare buttons, dial-in modems for legacy plant, voicemail-only numbers held for marketing reasons. Each of these needs an explicit migration plan.

2. Confirm broadband resilience

Hosted VoIP needs a stable internet connection. For most SMEs that means FTTP where it is available, with a 4G or 5G failover for sites where downtime is genuinely unacceptable. If your current broadband is FTTC or worse, the broadband upgrade should happen first.

3. Choose a hosted platform

The platform decision is mostly about three things: the integration with Microsoft 365 (do users want Teams Phone, or a separate softphone?), the reporting and call-recording requirements, and the contact-centre features for any sales or support teams. Get those right and the handset choice is the easy bit.

4. Plan the porting and cutover

UK number porting takes 2–10 working days depending on the losing carrier. Ports must be sequenced so the new system is fully tested before numbers move across. Done well, the cutover is invisible to customers — the same numbers ring on the new platform from the moment porting completes.

Common mistakes we see UK businesses make

  • Leaving it until the line is dead. Once the exchange withdraws, you are migrating in days, not weeks, and the cost of urgent installs goes up.
  • Forgetting the alarm and lift. A modern alarm signalling device on 4G is not optional after the switch-off — it is mandatory for business insurance in many cases.
  • Buying handsets before checking broadband. A perfectly specified VoIP system will sound terrible on a tired FTTC line. Broadband first, handsets second.
  • Picking the cheapest platform. The platform that wins on monthly cost often loses on call quality, support response and integration. The total-cost-of-ownership picture is rarely about the per-seat fee.
  • Ignoring porting timelines. Numbers cannot move on the day you ask. The migration plan has to start 4–6 weeks before the desired go-live date.

How Omni Telecom helps

Our IP Communications service is built around the migration that almost every UK SME now has to do. We handle the whole job end-to-end so business owners and IT managers do not have to chase three different vendors. In practice that looks like this:

  • Free site survey and connected-device audit. We catalogue every phone line, alarm panel, lift comms, card terminal and fax in the building, and write a single migration plan per site.
  • Broadband first, where needed. If your current connection is not up to hosted voice, we line up an FTTP or leased-line upgrade through our Business Broadband service before the phone migration starts.
  • Hosted VoIP with mobile twinning. Standard Omni packages include desk handset, softphone, mobile app, voicemail-to-email, call recording, and integration with Microsoft 365 where appropriate. Per-seat pricing, no minimum term gymnastics.
  • SIP trunks for sites that want to keep their PBX. If you have invested recently in an on-premise system, we replace the ISDN with SIP trunks rather than rip-and-replace.
  • Dedicated PSTN-replacement lines for alarms, lifts and EPOS. The "secondary" devices get the right replacement product first time — not a dial-tone workaround.
  • Number porting handled in-house. We manage the port from the losing carrier, sequence the cutover, and stand by during the change so any issue is dealt with in minutes.
  • Ongoing support from a UK helpdesk. No offshore call queue. Our UK engineers answer the phone, and on-site cover is available where the contract calls for it.

For a typical 20-user UK SME, the entire migration — audit, broadband upgrade, hosted VoIP install, porting and decommissioning of the old lines — takes 4–6 weeks from first conversation to fully cut over. The end state is a phone system that costs less per month, works on any device, follows the user, and is ready for the next decade rather than the last one.

Closing thought

The PSTN switch-off is not a marketing event. It is a hard regulatory deadline, and every UK SME has to deal with it before their local exchange withdraws. The businesses that handle it cleanly do three things: they audit early, they upgrade the broadband first, and they pick a partner that owns the whole migration rather than passing each step to a different supplier. Done right, the switch-off is the moment a UK SME finally moves to a phone system that fits how the team actually works in 2026.

Book a free consultation with Omni Telecom to discuss your IP Communications migration. We will run the connected-device audit at no cost and put a clear migration plan in front of you within a week.