The PSTN switch-off and fire alarm signalling: a guide for installers
Monitored fire alarms that send their signals over an analogue phone line can stop reaching the alarm receiving centre as the UK analogue network (PSTN) is withdrawn, which is due by 31 January 2027. Each one needs a visit to move it to an IP or 4G path, and a record of how every system signals.
Last updated 24 October 2026. Written by the CertSync team and checked against the standards.
What does the PSTN switch-off mean for fire alarms?
The UK analogue phone network is being withdrawn by 31 January 2027, and individual lines can be moved to digital services before then. A fire alarm that signals to its receiving centre over an analogue line may then stop doing so without any fault showing on the panel. Moving it to IP or 4G, ideally a dual path, needs a site visit and a test signal to the receiving centre.
1. What is being switched off, and when
The UK’s copper analogue phone network, the PSTN, is being replaced by digital services. The industry date for completing the move is 31 January 2027, but there is no single night when every line stops: lines are moved exchange by exchange and property by property, and a line can be moved earlier than the building owner expects.
Anything that relies on an analogue line rather than on a voice call is affected, and that includes the communicators many monitored fire and intruder alarms use to send signals to an alarm receiving centre.
2. Why the failure is silent
An alarm can carry on working locally, sounding and showing faults on its panel as normal, while its link to the receiving centre has already gone. The panel has no way to know that the line it signals over now behaves differently.
So the building may believe it is monitored when it is not. The only reliable check is a test signal sent to the receiving centre and confirmed by them.
3. What a migration visit involves
The usual answer is to replace the analogue communicator with one that signals over IP or a mobile network, and where the site needs it, a dual path that fails over from one route to the other.
On the visit, confirm how the system signals today, fit and configure the new communicator, make sure it has a suitable power supply, and send test signals that the receiving centre confirms it has received. Then record the new path and the test on the certificate or service record.
4. Recording it on the certificate
In CertSync, a fire alarm certificate with a receiving-centre section records the signalling path: PSTN / analogue, IP, 4G / GSM, dual path or not monitored. The field is optional and never stops you signing. Left blank, it prints as “Not recorded” and the site counts as unknown, not as unaffected.
Choosing PSTN adds a short note to the certificate. On a service record it also adds a C3 recommendation to replace the communicator, which you can reword, and which goes away if you change the path. Older certificates made before the field existed also count as unknown.
5. Finding every affected site
On the certificates list, the Signalling path filter shows every fire alarm certificate recorded as PSTN: a ready-made work list for migration visits. Add “Not recorded” to see the systems nobody has checked yet.
The filter works offline on the certificates saved on your device, and office staff can use it to plan the visits.
Frequently asked questions
- Will every analogue line stop working on 31 January 2027?
- Not all at once. That is the date the withdrawal is due to be complete, but lines are moved to digital services exchange by exchange, and a line can be moved earlier. Treat any alarm still on an analogue line as at risk now.
- How do I know whether an alarm signals over PSTN?
- Check the communicator fitted to the panel and ask the receiving centre how the system reports to them. Record what you find on the certificate so the next visit does not have to work it out again.
- Will the panel show a fault when the line stops working?
- Not necessarily. The alarm can keep working locally while its signals no longer reach the receiving centre. A test signal confirmed by the receiving centre is the reliable check.
- Is a dual-path communicator better than a single path?
- A dual path sends signals over two routes, usually IP and a mobile network, and fails over if one is lost, so a single failure does not cut the system off. Which is right depends on the site and what the receiving centre and insurer expect.
- Does recording the path stop me signing the certificate?
- No. In CertSync the field is optional. A blank path prints as Not recorded and counts as unknown, so it shows up when you filter for sites still to check.
Disclaimer
This guide is general information, not professional advice, and does not replace professional judgement, training or the guidance of your receiving centre, network provider or scheme body. Dates and arrangements for the analogue network are set by the network operators and can change. The contractor named on a certificate is responsible for what it certifies.
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