UK landline switch-off: moving your business phones to digital

Short answer: Openreach says the old analogue phone network (PSTN) switches off on 31 January 2027, and BT Business lists ISDN and ADSL going at the same time. For a business, the work is less about the phone on the desk and more about everything else plugged into those lines: alarms, card machines, lift lines, door entry, fax and franking. Make a list of every line and device, move calls to a digital service while keeping your numbers, then test each device on the new setup before the old line is ceased.

As of November 2026 that leaves roughly three months. If your provider has already written to you, read the letter carefully; if it hasn't, don't assume nothing on your premises is affected.

Step 1: Inventory every line and what uses it

Most small businesses have more copper lines than they think: one for the main number, an old one for the fax, one that the alarm company installed years ago, one in the lift. Walk the building and check the bills.

What to list	Where to find it	Why it matters
Every phone number you pay for	Phone and broadband bills, provider portal	Each needs a digital replacement or a decision to cancel
Line type (analogue, ISDN, broadband on ADSL)	Bill descriptions, provider	BT Business says ISDN, Featureline and multiline services can't be moved automatically and will stop on 31 January 2027 if not moved
Intruder and fire alarms with a dialler	Alarm panel, alarm company contract	May dial out over the phone line
Card machines / EPOS	Payment provider, till supplier	Older terminals may dial over a landline
Lift emergency phones	Lift maintenance contract	BT names lift lines as affected
Door entry, CCTV, fax, franking	The devices themselves, supplier	BT's help page lists these as line-dependent
Broadband that runs over the phone line	Router, bill	May need upgrading too
Staff or clients who rely on telecare	Ask	Openreach flags telecare and health devices as high priority

Write next to each item who supplies it and who will check it. That second column is where projects stall.

Step 2: Decide what replaces each line

For voice calls, the options usually come down to three:

Digital landline from your provider. Your existing number moves to a line that runs through your broadband router. Least change for staff, often the simplest for a shop with one or two numbers.
Cloud phone system (hosted VoIP). Numbers live with a cloud provider; calls ring desk phones, mobiles and laptops. Better for teams, opening-hours rules, call queues and working from anywhere.
Mobile only. Fine for some sole traders, but think about who answers the advertised number when you're on a job.

Keep your numbers. Ask the new provider to port each number you want to keep, and don't cancel the old service yourself before the port completes, or the number can be lost.

For devices, the fix depends on the device:

Alarms and lift lines: ask the supplier whether the unit works on a digital line, needs an adaptor, or should move to a mobile (4G) signalling unit.
Card machines: most modern terminals use broadband, Wi-Fi or a SIM. If yours dials over a phone line, ask the payment provider for a replacement.
Fax and franking: check whether the supplier offers an IP version, or whether you still need it at all.

The gov.uk guidance on the transition makes the same point for devices: contact the manufacturer or supplier, and when buying new equipment, check that it is compatible with digital lines or can use mobile connectivity.

Step 3: Plan the migration order

Broadband first. A digital phone line is only as good as the internet connection under it. Upgrade it if it relies on the old copper network.
Devices with a safety role next. Alarms, lift lines and anything connected to someone's health. Book the supplier visit before you book the phone change.
Main numbers last, and one at a time. Port the main number on a quiet day, not on a Monday morning or in your busiest season.
Keep the old bills for a few months. You'll want proof of what was there if something was missed.

Power cuts

An old analogue line carries power from the exchange, so a basic corded phone keeps working in a power cut. A digital phone line depends on your router having power. If calls are critical, ask your provider about battery back-up for the router, and keep a charged mobile as the fallback.

If you do nothing

Openreach says that lines not moved by the deadline may be placed on a temporary emergency voice-only service that keeps basic calls working "for a limited time" and may not support the features you use. BT Business also describes a "Protective Migrations" programme that moves some customers automatically, with notice by email or post. Neither covers your alarm or lift; they only keep a voice line alive.

A moment to rethink call handling

Moving to a digital or cloud system is also the cheapest time to change how calls are answered. Options worth considering while you're at it:

call routing by opening hours, with a different message out of hours
ringing several phones at once, including mobiles
voicemail delivered to email or a shared inbox
a text back to callers you missed
an AI assistant that answers routine questions or takes messages when nobody can pick up

None of these is required. But a project you have to do anyway is a good excuse to stop losing calls.

Step 4: What to test after each change

Test on the day of each switch, with the supplier on the phone if possible:

[ ] Inbound calls to every number you ported, from a mobile and from another landline
[ ] Outbound calls show the right caller ID
[ ] Out-of-hours routing and voicemail work
[ ] Alarm panel can signal to the monitoring centre (ask them to confirm receipt)
[ ] Lift emergency phone connects
[ ] Card machine takes a real payment
[ ] Door entry calls the right handset
[ ] Router stays up during a short planned power-off, if you have battery back-up
[ ] Your provider has the correct premises address registered for emergency calls

Then update the phone number on your website, Google Business Profile and invoices only if it changed. Ideally it didn't.

FAQ

Do I have to change my business phone number?

Normally no. Numbers can be ported to a digital landline or a cloud phone provider. Ask about porting before you sign anything, and don't cancel the old line first.

Will my existing desk phones still work?

Some will plug into the router's phone socket on a digital landline. For a cloud system you may need IP handsets or a softphone app. Ask the new provider before buying anything.

Is the date still 31 January 2027?

Openreach's own page states that date as of November 2026. Check it again with your provider, as programmes can change.

Can I just use mobiles instead?

For a very small business, sometimes. You'll still need a plan for alarms, card machines and any device that dialled over the landline.

If you're moving to a digital phone system and want calls routed, recorded or answered properly from day one, tell us what's on your lines today.