If you've had a letter from your phone provider, or heard someone mention that 'the old phone lines are going', you may be wondering what it actually means for your business. The short answer is that the traditional copper telephone network in the UK is being retired, and every business, school, charity and care provider still using it will need to move to a digital alternative. The good news is that with a bit of planning, the switch is usually straightforward.
Here's a plain-English guide to what's happening, what could be affected, and what to do next.
What is the PSTN and ISDN switch-off?
The PSTN (Public Switched Telephone Network) is the analogue phone network that has carried landline calls in the UK for decades. ISDN is an older digital service that runs over the same copper infrastructure and is still common in offices with multiple lines or a traditional phone system.
Openreach and the major providers are replacing both with an all-digital network, where calls travel over an internet connection instead. This is often described as moving to VoIP (Voice over Internet Protocol). The deadline for the switch-off has been moved before, and is currently expected to complete by January 2027. In many areas, new analogue and ISDN lines can no longer be ordered, and some exchanges have already been migrated.
In other words, this isn't a distant problem. If your business still relies on these lines, now is a sensible time to act rather than waiting for your provider to force the change.
How do I know if my business is affected?
You're likely to be affected if any of the following apply:
- You have a traditional landline plugged into a phone socket on the wall
- Your office uses an on-site phone system (often a box in a cupboard) connected to ISDN lines
- Your broadband is ADSL or an older package bundled with a phone line
- You haven't reviewed your phone contracts in several years
If you're not sure, your phone bill is a good starting point. Look for references to analogue lines, ISDN2, ISDN30 or line rental. An IT support provider can also check this for you quickly.
It's not just your phones
This is the part many organisations miss. Plenty of equipment quietly uses a phone line to communicate, and some of it may stop working, or behave unreliably, once the line is switched over. Common examples include:
- Intruder and fire alarms that dial out to a monitoring centre
- Lift emergency phones
- Door entry and gate intercom systems
- Older card payment terminals
- Franking machines
- Fax machines
- Telecare and personal alarm devices, which is particularly important for care providers
- CCTV or building management systems with dial-up connections
It's worth walking around your premises and making a list of anything connected to a phone socket. Then speak to the supplier of each device to ask whether it's compatible with a digital line or needs upgrading. For anything safety-critical, don't leave this until the last minute.
What about power cuts?
Traditional copper phone lines carry their own power, so a basic landline will often keep working during a power cut. Digital phone services rely on your router and equipment having power. If your organisation needs to make calls during an outage, for example a school, a care setting or a business with lone workers, you'll want to consider battery backup for key equipment, or have mobile phones available as a fallback. A good provider will discuss this with you rather than leave it as an afterthought.
What are your options?
There's no single right answer, as it depends on the size of your organisation, how you work and what you already use. The main options are:
Hosted VoIP phone system
Your phone system lives in the cloud rather than in a box in your office. Staff can use desk phones, a softphone app on their computer, or a mobile app, and calls can follow people whether they're in the office or working from home. This suits most small and medium-sized organisations.
SIP trunks
If you have a relatively modern on-site phone system that you want to keep, SIP trunks can replace ISDN lines and connect your existing system to the digital network. This can be a good stepping stone, although it's worth checking how long your current system will remain supported.
Microsoft Teams Phone
If your team already uses Microsoft 365 and Teams, you can add calling directly into Teams. For many organisations this keeps everything in one place, though it isn't the right fit for everyone, particularly where staff need traditional desk phones or complex call routing.
Can I keep my phone number?
In most cases, yes. Your existing numbers can usually be transferred (known as 'porting') to your new provider. It's one of the first things to confirm when planning a move, as customers and suppliers know your number and changing it would be disruptive.
A simple plan to follow
- Find out which lines and contracts you have, and when they end
- List every device connected to a phone line, not just the phones
- Check your internet connection is reliable enough to carry voice calls
- Decide which phone option suits the way your team actually works
- Plan for power cuts and emergencies
- Schedule the move at a quiet time, with number porting arranged in advance
Your broadband matters more than ever here. If calls will depend on your internet connection, a stable, properly configured connection is essential, and in some cases an upgrade or a backup connection is worth considering.
Don't wait for the deadline
The organisations that find this switch stressful are usually the ones who leave it until something stops working. Moving in your own time means you can choose the right setup, test it properly and avoid surprises with alarms or payment terminals.
If you'd like a hand working out where you stand, Cloud 4 Sure helps businesses, schools, charities and care providers across Sussex, Surrey, Hampshire and Kent move to VoIP calmly and without fuss. Get in touch to book a free IT health check and we'll take a look at your current lines, connected equipment and internet connection, then talk you through your options in plain English.