The UK’s Public Switched Telephone Network (PSTN) system is due to be completely shut down by 31 January 2027. The PSTN is the backbone of many systems, such as fire alarms, door entry systems, payment terminals, lift emergency and medical monitoring equipment, all of which are connected to the PSTN. Fire Alarms and Intruder Alarm Systems Might ShutdownMany may think that fire and intruder alarms send communications via mobile networks or the internet. However, a large number of systems, most notably the older commercial and residential systems, send communications over the PSTN. How To Fix An Alarm System Before The Switch OffThe solution will vary depending on the alarm system.