what is voip and how does it work for business?

VoIP (Voice over Internet Protocol) lets businesses make and receive calls over the internet instead of copper landlines; services such as SIP trunking or Microsoft Teams Phone convert voice to data packets. It needs reliable broadband, a VoIP handset or adapter, and often at least one analogue line still to be checked.

A small office we worked with moved to a cloud phone system and assumed the cut-over was just phones and numbers. Their alarm, wired to an analogue line kept in a store cupboard, failed on day two until an adaptor was fitted. Most businesses we speak to still have at least one legacy analogue line — usually an alarm, a door entry, a lift line, or a fax number — that no-one has thought to migrate ahead of the PSTN switch-off. It is rarely the phones themselves that trip a business up, it is the forgotten “back of the cupboard” line.

The takeaway is simple: VoIP will usually save money and add features, but the technical and business risks come from overlooked devices and bandwidth issues. Below are two practical actions to get the switch right without disruption.

Action 1 — Audit connectivity and legacy devices

Start with an audit that covers three things: the internet connection, endpoint compatibility and any analogue services. Audit first — list every phone number and every device wired into a copper line (alarms, lifts, entry systems, faxes). Include extension numbers, DDI ranges and handset models.

Internet: run a sustained throughput test at peak hours and verify latency and jitter with your IT team or provider.
Endpoints: check whether handsets are SIP-capable or need analog telephone adapters (ATAs).
Analogue devices: identify which devices must stay on copper or need a specific analogue-to-IP adaptor.

When you have that list, ask potential suppliers for a technical sheet and a short pilot. A clear starting point is to read the supplier’s service detail on business phone systems and VoIP and match it to your audit. Keep one paragraph of the audit as the project brief for whoever will do the cut-over.

Action 2 — Migrate in stages and control risk

Run the migration in phases: pilot, parallel run, cut-over. For the pilot, pick a small team to use the new system alongside the old one so you can test call routing, voicemail, and remote working. Keep critical analogue services live until you have verified replacements or adaptors.

Pilot: 1–3 users for a week to validate features and training needs.
Parallel run: route inbound calls to both systems for 48–72 hours and monitor call quality.
Cut-over: schedule the final switch outside business hours, notify staff and suppliers, and have a rollback plan.

During the staged migration, check numbers are ported, test every analogue device with its adaptor, and log any vendor support calls. Train reception and front-line staff on basic troubleshooting (handset reboot, network check) so the first line of support is internal. After cut-over, monitor call quality and billing for the first month to catch configuration or routing errors quickly.

If you want help with the audit or a staged plan, our team can produce a short migration brief that limits downtime and avoids unexpected analogue surprises. A small investment in planning saves lost sales, emergency engineers and customer service headaches.

FAQ

Will my alarm or lift stop working when I move to VoIP in the UK?

Possibly — many alarms and lifts use a dedicated analogue line. Test each device before cut-over and either fit an analogue-to-IP adaptor or retain a separate line until the device is migrated and verified.

How many analogue lines do businesses forget when switching to VoIP?

Most of the businesses we work with still have at least one legacy analogue line — usually an alarm, a door entry, a lift line, or a fax number — that no-one has thought to migrate ahead of the PSTN switch-off.

Can I keep my existing phone numbers when I move to VoIP?

Yes — number porting is standard with UK providers, but you should ask the supplier for a porting timeline and schedule the port to avoid service gaps; ensure the provider confirms any temporary routing during the move.