Switching from landline to VoIP

Why businesses are switching now

Openreach says that "On 31 January 2027, all traditional phone lines will be going digital." For businesses on ISDN it is just as direct: "All services supported by ISDN need to be migrated to an IP service by January 2027 or your service will be ceased." If a line has not moved in time, Openreach says the service may be limited and may be moved to its Emergency Voice and Access Continuity (EVAc) service: a temporary, emergency voice-only service that may not support the calling features you use today. It is a safety net rather than a destination.

The good news is that the move is a chance to upgrade, not just to replace. On a VoIP phone system your numbers live on the system rather than on a copper line, so calls can ring a desk phone in the office, an app on a laptop at home and a mobile on the road. Menus, hunt groups, call queues, voicemail to email and call recording become settings rather than hardware. Openreach also notes that you can usually keep your existing business phone number when you switch, and VoIP numbers for business explains how those numbers work once they move.

If you are still weighing up the two, VoIP vs landline sets them side by side, and what is a VoIP landline explains the digital landline option for a single line. For the national timetable, our sister site Forever Communications covers the PSTN switch-off UK in depth.

How to switch from landline to VoIP in seven steps

These are the steps we work through with businesses moving off landlines. The audit at the start is the step that saves the most time later.

1. Audit your lines and devices. List every number and line on every bill, then find what is plugged into each one: phones, a phone system, fax, intruder and fire alarms, lift emergency phones, door entry, card terminals and franking machines. Note any broadband that runs over the same line.
2. Choose a VoIP platform. Match the platform to how your people work: in Microsoft Teams, on mobiles and laptops, at desks or in a contact centre. The table below is a quick guide, and best VoIP phone system goes further.
3. Check your connection and network. Confirm upload speed, latency and router settings against our VoIP requirements checklist, and decide whether calls need a backup connection.
4. Keep your numbers. Collect a recent bill and plan the port. Port your landline number to VoIP explains the letter of authority, matching details and porting date.
5. Sort handsets, apps and adapters. Decide who needs a desk phone, a cordless handset, a headset or just the app, and which analogue devices need a VoIP adapter.
6. Plan special lines. Ask your alarm, lift, door-entry and card-terminal suppliers how each device should connect after the switch, and book tests.
7. Go live and test. Build call flows, train users, port the numbers on the agreed date, test every number and device, then cease the old lines. Our guide to VoIP phone system installation shows how that runs.

If you are replacing analogue business phone lines rather than a whole phone system, the same steps apply on a smaller scale. For a printable version, our sister site has a PSTN switch-off checklist with a line audit template.

Choosing what to switch to

There is no single right answer, which is why Forever Systems supplies several VoIP platforms and recommends by fit. These starting points cover most businesses:

BT Cloud Voice is also available, supplied by our sister company Forever Communications through cloudvoice.cloud. If you are moving a multi-line or ISDN system, ISDN to VoIP and multi-line VoIP phone systems cover the extra decisions.

Your broadband and network

VoIP sends each call as data, so the connection matters more than the handset. Cisco's figures for one call, including network overhead, are about 87.2 kbps in each direction with the G.711 or G.722 codecs and about 31.2 kbps with G.729. Upload speed counts as much as download, and steady latency matters more than headline speed: Cisco summarises the ITU-T G.114 guidance as up to 150 ms one-way delay being acceptable for voice.

Three things trip up many switches:

• Broadband on the line you are leaving. If your internet connection runs over the same line, arrange the replacement connection before the old line is ported or ceased. Our sister site explains broadband for VoIP, and busy sites may justify a leased line for VoIP.
• Router settings. 3CX, for example, advises turning SIP ALG off on the router. See VoIP router settings.
• Priority for voice. On a shared office network, VoIP QoS settings keep calls clear when someone uploads a large file.

We can check all of this before you commit, as part of the requirements check.

Handsets, adapters, power and special lines

You do not have to put a desk phone on every desk. Many people work happily with an app and a headset, while reception and heavy phone users often keep a handset; softphone vs desk phone compares the two. VoIP desk, cordless and conference handsets can be bought outright or, in some cases, included in your monthly rental, with the options confirmed at quote. VoIP handsets for business covers the device types and which work with each platform.

Power. Openreach points out that digital phone lines need power to work, unlike old copper lines powered from the exchange. Phones that take Power over Ethernet from a network switch keep working in a power cut if that switch and the router are on a UPS. If anyone relies on a landline for health or safety reasons, plan for that early.

Analogue devices. An analogue telephone adapter can connect some older phones, door entry and franking machines to VoIP. Alarm diallers, lift emergency phones and card terminals need a plan agreed with their own supplier; our sister site's guide to alarm and special lines explains the options.

How we help you switch

Forever Systems supplies hosted 3CX, Microsoft Teams Phone, Webex Calling, Forever UC, Forever Teams and SIP trunks, so we can recommend the platform that fits how you work. We can help with:

• A line and device audit to find every connected device before port day
• A requirements check of your connection, network and router
• Platform choice, new numbers and the port of the numbers you keep
• Handsets, apps and adapters, provisioned for your system
• Call flows, training and go-live, then help with changes afterwards

Contact us with a recent phone bill and a rough count of users and sites, and we will map out your switch.