The PSTN Switch-off: January 2027

How will the PSTN Switch-off affect my alarm system?

A significant change to the UK’s telephone network means that intruder alarms and fire alarms which signal over the telephone network will stop working in January 2027.

Here’s an overview of what’s happening, when and what you need to do about it.

  • BT and other telephone service providers are modernising the landline network, known as the Public Switched Telephone Network (PSTN), switching from analogue to digital or Internet Protocol (IP). The outdated copper telephone lines are being replaced with fibre optic ones, and digital technology known as Voice over Internet Protocol (VoIP) will facilitate landline calls via broadband.

    The change is driven by a growing demand for faster networks and connectivity, compounded by the increasing difficulty and expense of maintaining the PSTN.

  • Upon completion of the upgrade, intruder and fire alarms reliant on an analogue telephone line will fail to communicate with the alarm receiving centre, rendering them non-functional.

  • If your alarm currently signals via the telephone network, you’ll need to upgrade your signalling device to a digital one. However, if you have an old security system supported only by circuit-switched technology, it won’t be compatible with any other technology and will need to be replaced.

  • Signalling via the mobile network means you could save costs. For example, you’ll no longer have any call charges relating to your intruder alarm on your phone bill, and you won’t need to pay for line rental. Also, there will be no risk of your phone cable being cut and disabling your alarm.

  • BT will be phasing out the PSTN by January 2027, with other providers following a similar timeline. However, BT is already discontinuing analogue lines in certain local exchanges as it transitions customers, underscoring the importance of taking action now.

  • If you have a security system connected to an analogue phone line, your security provider should be in touch. However, please contact us if you have any questions or would like to discuss an upgrade.