Is Your Alarm Ready for the 2027 Phone Line Switch-Off?
Updated: Sep 29
Updated September 2026 · Kelvin Pay, Protect CSM
The old copper phone network is being switched off for good. BT has confirmed that all remaining analogue (PSTN) and ISDN lines will be switched off on 31 January 2027, with every line moved to digital services by then.
Most people think of this as a phone and broadband change. But plenty of intruder alarms, fire alarms and door entry systems in Hampshire and Surrey still rely on that old phone line to call for help, and many owners don't know theirs does.
Which alarms are affected?
Your alarm could be affected if it:
Dials out when it's triggered, calling your mobile or a family member through the phone line (often called a speech or auto-dialler)
Is monitored, sending signals to a monitoring centre over the phone line
Has a cable running from the alarm panel to your phone socket
Is part of a fire alarm, lift line, door entry or telecare system that uses a phone line
Your alarm is unlikely to be affected if it:
Is a bells-only alarm that makes a noise but doesn't call anyone
Connects through Wi-Fi, your broadband router or its own SIM card, for example alarms you control from an app on your phone
Why it matters
When the copper line is switched off, an alarm that relies on it may carry on working locally but stop reporting to anyone, with no obvious warning. You might not find out until the day you need it.
If your home or business insurance, or a police response, depends on your alarm being monitored, a lost connection could also cause problems with your cover.
There's a second catch. Digital phone lines run through your broadband router, so in a power cut the line can go down too, unless the router has a battery backup.
How to check your alarm
Look at your alarm panel. Is there a cable going to your phone socket?
Does your alarm call you, or a monitoring company, when it's set off?
Has your phone provider already moved you to a digital line, so your phone now plugs into the router? If so, test your alarm's dial-out straight away. It may already have stopped working.
If you answered yes to any of these, or you're not sure, get it checked.
What's the fix?
In most cases your existing alarm doesn't need replacing. The part that sends the signal (the communicator) can be upgraded to a modern one that signals over the internet, the mobile network, or both. A dual-path communicator uses two routes at once, so if your broadband drops, the mobile signal takes over.
We can check your system, tell you honestly whether it's affected, and fit the right upgrade. We also work on alarms installed by other companies.
Don't leave it until January
With millions of lines to move before the deadline, installers are getting busier as 2027 gets closer. Getting your alarm checked now means you won't be caught out.
Book a free survey: call 01420 375376 or book online. We cover Liphook, Bordon, Alton, Petersfield, Haslemere, Farnham, Guildford and surrounding areas.
Comments