The UK phone line switch-off: what small businesses need to do

This guide is for UK small businesses that still have equipment connected to an old telephone socket. Openreach is moving the old copper PSTN and ISDN network to digital, internet-based services. Timetables have moved, but the direction has not: this is happening. Do not leave it until a supplier tells you a service is about to stop, because the less obvious equipment is often the part that takes time to replace.

Understand what is changing

Traditional phone services carried calls over the public switched telephone network, often called PSTN, and ISDN was a digital business service on the same older network. Those services are being retired as providers move customers to digital alternatives. A digital service uses your broadband connection or mobile network instead. It may still use the same desk handset and phone number, but it is not powered by the old line.

Step 1: find everything connected to a phone line

Walk through each site with someone who knows the building and someone who knows the services. Look at comms cupboards, reception, plant rooms, lifts, alarm panels and outbuildings. Ask each supplier what connection its equipment uses and whether it will work after a move to digital. Do not accept "it should be fine" as an answer; ask for the required replacement and any test process in writing.

Items businesses often miss

• Intruder alarms, fire alarms and CCTV diallers that call an alarm receiving centre.
• Lift emergency phones and intercoms, including services managed by a landlord.
• Card payment terminals, fax machines, franking machines and old EPOS links.
• Door entry, gate controls, boiler monitoring and remote plant alerts.
• Careline, lone-worker and welfare devices where staff or visitors rely on them.
• Analogue phones in meeting rooms, stock rooms or a manager's home office.

Record the device, location, supplier, account number, number dialled and action needed. If you have cameras or access control, speak to the people who maintain them as well as the phone company. TSS can help connect the wider picture through business CCTV support and access-control systems where needed.

Step 2: check what broadband will carry the service

Ask for the available speed, the likely upload performance, router suitability and what happens if the main connection fails. A business with a busy reception or remote workers may benefit from a second connection or mobile failover. Our business broadband guide sets out the questions worth asking before you order. Do not assume domestic broadband, an ageing router or a single WiFi access point will suit a phone system without checking.

Plan call quality, not only speed

• Prioritise voice traffic on the network so large downloads do not spoil calls.
• Use wired connections for fixed desk phones where practical.
• Check coverage in warehouses, yards and meeting rooms if staff use softphones.
• Test the planned system at busy times, not only after hours.

Step 3: choose the right digital replacement

For most small businesses, hosted VoIP is the straightforward replacement. Calls run through an app, a desk handset or both, while the provider hosts the phone platform. You can usually keep existing geographic numbers, set opening-hours rules, route calls to mobiles and add users without installing a phone cabinet on site. It suits teams that split time between home, office and customer visits.

There are trade-offs. A cloud phone system depends on connectivity and power, and not every old handset or alarm can be connected through an adapter. Some sites may need a new router, data cabling or a separate mobile-based service for a critical device. Start with your actual call flow: who answers, where calls go out of hours, which number is on stationery and what must keep working. Compare this with the options on our business phone systems page.

Step 4: plan for power cuts and 999 calls

An old copper phone could often keep working during a local power cut because it carried its own power. Digital phones usually need power for the router, modem, network and handset. That means you must decide what is acceptable for your premises. A small battery backup may keep key equipment running for a limited time; a larger site may need a more formal resilience plan. Mobile phones are useful, but check signal indoors and make sure key staff know the fallback number.

Consider lifts, alarm signalling and any device used to call for help separately. The responsible supplier must confirm that its replacement can make an emergency call in a power failure or describe the alternative. Test the fallback arrangement and tell staff where it is documented. Never rely on an untested mobile signal or a battery that has not been maintained.

Step 5: make the move in a controlled order

Begin the audit now, then order replacement services early enough to allow installation and testing. Keep a list of old numbers and decide which must be retained. Where number porting is involved, confirm the date and avoid changing account details at the last minute. Set up the new handsets or apps, call groups and voicemail first, then test incoming, outgoing and emergency procedures with the people who will use them.

What to do next

Make the device inventory, speak to each equipment supplier and review the broadband behind your phone service. TSS helps businesses in Bury, Greater Manchester and Lancashire with digital calling and connectivity. Book a free, no-obligation chat if you want someone to help turn the audit into a practical plan.