VoIP and Business Phone Support

The PSTN switch-off: what it means for your business

BT and Openreach are closing the UK's copper Public Switched Telephone Network. Industry reporting, including ISPreview's coverage of Openreach updates in 2026, puts the final switch-off on 31 January 2027, after the original December 2025 target was moved back. After that, phone calls run over broadband as digital voice or VoIP.

Your main phone line is the easy part: your provider moves it to a digital service or you move to a hosted VoIP system. The harder part is the equipment nobody remembers is plugged into a phone socket:

• Intruder and fire alarms that dial out to a monitoring centre
• Lift emergency phones
• Franking machines and older card payment terminals
• Door entry and gate intercoms
• Fax machines, still common in some healthcare and legal settings
• Telecare alarms for vulnerable staff or relatives

We walk through the building with you over video, list every device on an analogue line, and tell you which supplier to contact about each one.

Fixing common VoIP faults

One-way audio and dropped calls

The most common cause is SIP ALG, a router feature meant to help VoIP that usually breaks it by rewriting SIP messages. Calls connect but audio only goes one way, or calls drop at a fixed interval as registrations time out. We turn SIP ALG off, check NAT and firewall rules for SIP signalling and the RTP media ports your provider uses, and test.

Handsets not registering

Desk phones need power (usually PoE from the network switch), an IP address from DHCP, the right provisioning settings and a working path to the provider on port 5060 or 5061 for TLS. We work through each in turn.

Poor call quality

Voice is sensitive to jitter and packet loss rather than raw speed. A call needs very little bandwidth, but it suffers when the same connection is busy with cloud backups or video. We set QoS on your router or switch to prioritise voice, and if your broadband upload is the bottleneck we will say so. See broadband and router support and network support.

Choosing a phone system

For most small businesses the choice is between a hosted VoIP system (a cloud PBX with desk phones and apps), Teams Phone if you already live in Microsoft Teams, or a simple digital voice line for very small sites. We do not sell phone systems or lines, so our advice is independent. We help you compare call routing, hunt groups, out-of-hours messages, call recording, mobile apps, number porting and how each option handles 999 calls and your registered address.

If Teams is your main tool, see Teams support for how calling plans, Operator Connect and Direct Routing differ.

Moving to VoIP without losing your number

Your existing geographic numbers can be ported to a new provider. Porting is handled by the new provider, but it fails surprisingly often because of details: the account holder name, the installation address and the exact numbers in a range all need to match the losing provider's records. We help gather the right information and schedule the port so calls are not lost on the day.

We also check that the office network is ready: enough PoE switch ports, a separate voice VLAN where it helps, and that the router and firewall will not get in the way.

One difference catches people out: an old analogue phone kept working in a power cut because the line carried its own power. VoIP phones, routers and PoE switches do not. If phones must work during an outage, we suggest a small UPS for the router and switch, and making sure staff have a charged mobile for emergency calls.

Cost

VoIP troubleshooting is £45 an hour + VAT, with a 30-minute minimum and then 15-minute blocks. A PSTN switch-off review for a small office usually takes an hour or two. Office-wide moves to a new phone system and any on-site work are quoted. Get in touch or request a quote.

What it costs

Support plans from £25 a month + VAT, or £45 an hour + VAT for one-off fixes. Pick a plan if you want it looked after every month, or pay by the hour for a one-off job.

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