BT’s analogue network in the UK, the Public Switched Telephone Network (PSTN), is shutting down. This will affect millions of devices that are still connected to the network, including security and fire alarm systems.

The  (PSTN) is used for telecommunications like phone calls and faxes and used by fire and security providers for sending alarm signals to the central station. BT later introduced the Integrated Service Digital Network (ISDN) to provide internet access that was faster than the original dial-up system. After decades of service in the UK, both networks will now permanently close within the next 12 months.