Traditional landlines are running out of road. BT and the other UK networks are switching off the old PSTN and ISDN network, with the national deadline now set for January 2027. If your office still relies on copper phone lines, you will need a plan — and for most Cardiff and South Wales businesses, that plan is VoIP.

This guide explains what switching from landline to VoIP actually involves, what you need in place, and how to do it without dropping calls or losing your numbers.

What is VoIP?

VoIP (Voice over Internet Protocol) sends phone calls over your internet connection instead of a copper landline. Calls still ring on a desk phone, a mobile app or a headset — the difference is the path they take.

Instead of renting analogue lines from a traditional provider, you use a cloud phone system or hosted PBX. Your numbers stay the same (including a local 029 Cardiff number), but the system itself lives in the cloud. That is why people also search for cloud phone systems Cardiff, hosted phone systems and business phone systems Cardiff when they start this process.

Why switch from landline to VoIP now?

1. The PSTN switch-off is coming

New analogue lines are already hard to get. Keeping old ISDN or PSTN services until the last minute usually means rushed quotes, limited kit and higher cost.

2. Cost

Most businesses cut call charges and line rental when they move to VoIP. Unlimited UK landline and mobile bundles are common. You stop paying for unused copper lines.

3. Flexibility

Staff can take the same business number on a desk phone, laptop or mobile. Hybrid and multi-site teams stay on one system.

4. Features that landlines never had

Auto-attendant (“press 1 for sales”), call queues, voicemail-to-email, call recording, presence and Microsoft Teams calling are standard on modern VoIP phone systems Cardiff providers install.

5. One network

Voice and data share the same connection. Pair VoIP with a leased line or solid business broadband and you get clearer calls and fewer “the line is down” mornings.

What you need before you switch

A reliable internet connection

VoIP is only as good as the link it rides on. Shared home broadband can work for a tiny team. A busy office, call-heavy team or video-heavy workflow is better on business broadband or a leased line. Quality of Service (QoS) on the router keeps calls from competing with file uploads.

The right phones

You can keep using some IP-ready handsets, buy new desk phones, or go app-only. Many Cardiff offices mix reception desk phones with softphones for people who move around.

Your existing numbers

You do not have to change number. Number porting moves your current landline or 029 numbers onto the new VoIP system. Plan this early — porting has a lead time.

A provider who does the whole job

The switch is not just a software login. Cabling, Wi-Fi, handset rollout, porting and training all matter. That is why local business telecoms Cardiff firms package phones, lines and support together.

Common worries (and the real answers)

“What if the internet goes down?”

Build in failover: a second broadband circuit, 4G/5G backup, or automatic divert to mobiles. A leased line plus backup is the usual setup for firms that cannot miss calls.

“Will call quality be worse?”

On a properly specified connection, VoIP is clearer than old copper. Poor quality almost always means undersized broadband, bad Wi-Fi or no QoS — not VoIP itself.

“Can I keep my 029 number?”

Yes. Port it to the new system. A local Cardiff number still builds trust even if some of the team work remotely.

“What about alarms, franking machines and chip-and-pin?”

Treat each analogue device separately. Do not assume it will work on VoIP without checking.

“Is this only for big companies?”

No. Small Cardiff firms switch because line rental and call rates add up, and because the old network is closing.

Switching in Cardiff and South Wales

Local context matters. Buildings in the city centre, Cardiff Bay and older stock can have patchy indoor signal and mixed cabling. A provider who will survey the site, install data cabling and Wi-Fi, and stay for support is more useful than a remote portal and a box of phones.

Crystal Voice Data helps businesses across Cardiff and South Wales move from landline to VoIP as part of a wider package: VoIP phone systems, cloud phone systems, leased lines, business broadband, Wi-Fi and data cabling, plus installation, training and ongoing support.

Ready to plan the switch?

If you are still on landline or ISDN, the useful question is not whether to move to VoIP — it is when, and how cleanly. Start with a site survey and a list of every number and analogue device you have. From there you can choose a cloud phone system that keeps your 029 numbers, works with the way your team already works, and is ready before the PSTN switch-off.

Get in touch for a straightforward assessment of your current lines and what a VoIP cutover would look like for your office.