Broadband/VoIP

ISDN Switch-Off: What UK Businesses Need to Do Before January 2027

If your business still uses a traditional phone line or ISDN, it is running on borrowed time. The UK’s old copper phone network is being retired, and everything that relies on it has to move to digital, internet-based services.

The target date for finishing the job is 31 January 2027. From today, that is roughly four and a half months away, and it includes the Christmas shutdown. This guide explains what’s changing, what could stop working, and a practical checklist to get your business sorted in time.

What’s being switched off?

Two old technologies are going:

• PSTN (Public Switched Telephone Network) – the analogue network behind traditional landlines. If you pay “line rental” or “WLR” (Wholesale Line Rental), you’re using it.
• ISDN (Integrated Services Digital Network) – a business version that carries several calls at once. ISDN2 is typically used by small offices needing a couple of simultaneous calls; ISDN30 is used by larger phone systems needing many.

Openreach, which runs most of the UK’s phone line network, is replacing them with an all-digital network where calls travel over broadband using internet protocol (IP). In practice, that means phone calls move to VoIP.

The timeline so far

The extra time was welcome, but it hasn’t changed the direction of travel. Your provider may also move your lines before the final date, so don’t treat January 2027 as your deadline to start thinking about it.

Is this affecting my business?

Probably, if any of these sound familiar:

• Your phone bill mentions line rental, WLR, PSTN, analogue or ISDN
• You have a phone system box on the wall with phone lines plugged into it
• Your broadband comes “with a phone line”
• Equipment in your building (alarms, card machines, lifts) has a phone cable going into the wall

What could stop working

The obvious one is your phones. The ones people forget are the devices that quietly use a phone line in the background:

• Analogue phone lines and the handsets plugged into them
• ISDN2 and ISDN30 lines, and the on-site phone systems that depend on them
• Intruder and fire alarms that dial out to a monitoring centre
• Lift emergency phones
• Card payment terminals (PDQ machines) that connect over a phone line
• Franking machines that dial in to top up or update
• Fax machines
• Door entry systems that call out to a phone
• Telecare and personal alarms, for example for lone workers or residents

Your ISDN switch-off checklist

1. Audit every line and device

Walk round the building. List every phone number you have and what each one is used for. Look for anything with a phone cable: alarm panels, lift cars, card machines, the franking machine, the old fax in the corner, the door entry panel.

2. Check your bill and your contracts

Your phone bill will show which lines you’re paying for, including any you’d forgotten about. Note the contract end dates and any early exit fees so you can plan the move without paying twice.

3. Choose your new phone system

Cloud VoIP replaces both the lines and the on-site phone system. Edison VoIP is £10 per extension per month, with desk phones free on contract, and includes auto attendant, call queues, call recording and voicemail as standard.

4. Sort the right broadband

Once calls run over the internet, your broadband matters more. The good news is you no longer need a phone line underneath it. SOGEA is fibre broadband that runs without a traditional phone line; FTTP is full fibre direct to your premises.

5. Keep your numbers

In most cases your existing numbers can be moved (ported) to your new VoIP system, so customers, suppliers and your Google listing all stay the same. Don’t cancel your old lines yourself before the port is complete, as cancelling a line can mean losing the number.

6. Speak to your alarm, lift, card machine and franking suppliers

Ask each one directly: “Will this work after the switch-off, and if not, what do you recommend?” Many now offer digital or mobile-SIM based alternatives. Get the equipment tested once your lines have moved.

7. Plan for power cuts

Old analogue phones drew power from the line, so they often kept working in a power cut. Digital phones and routers need mains power. Keep charged mobiles available for emergency calls, and tell your provider if anyone at your premises relies on a landline for health or safety.

8. Set a timeline and stick to it

Work back from 31 January 2027, remembering that December disappears quickly:

• This month: audit your lines and devices, and gather your bills
• Next month: choose your phone system and broadband, and start number porting
• Before Christmas: go live, test alarms, card machines and anything else that used a line
• January: tidy up, cancel what’s no longer needed once numbers have moved

Porting and installation aren’t instant, so leave yourself several weeks of breathing room.

What if you do nothing?

Your provider will contact you about moving to a digital service, and your lines will be migrated eventually. The risk is that it happens on someone else’s schedule, with less choice, and you discover the hard way which devices didn’t make the move. Leaving it late also means competing for installation slots with everyone else who waited.

Replace it once, and do it properly

The switch-off is a good moment to stop paying for lines you don’t use and to bring broadband, phones and mobile under one roof. Edison Networks has been helping UK businesses with their communications since 2013, and our team has more than 30 years’ telecoms experience. We’ll audit your lines, port your numbers and set everything up, so there is one provider, one bill and one person to call.

Related: Business VoIP phone systems | Business broadband