Check devices & alarms

Security and fire alarms on landlines

In brief

  • Monitored burglar alarms, fire alarm communicators, and panic alarms that dial out over the phone line may stop working after the switch.
  • The alarm panel itself still detects intrusions and fires. It is the signalling path to the monitoring centre that is affected.
  • Contact your alarm company or monitoring provider to check compatibility and upgrade the communicator if needed.

Which alarm systems are affected?

Any alarm that uses the phone line to communicate is potentially affected by the move from analogue to digital voice. This includes:

How to tell if yours uses the phone line

Look at the alarm control panel (usually a metal box in a cupboard, utility room, or near the front door). Follow any cables coming out of it. If one goes to a phone wall socket or a phone line junction, the alarm uses the PSTN.

If there is a separate small box labelled "communicator", "dialler", or "signalling device", that is the part that talks to the monitoring centre. Check where its cable goes.

Some newer systems use a SIM card (mobile) or a broadband connection instead of, or as well as, the phone line. If yours has a SIM or connects to your router, it may already be independent of the old phone line, but you should still confirm with the alarm company.

The risks

Signalling failure

Alarm communicators that use voiceband signalling (Contact ID, SIA, or similar protocols sent as audio tones over the phone line) are not guaranteed to work over digital voice connections. The tones can be distorted, delayed, or dropped. A failed signal means the monitoring centre does not know the alarm has been triggered.

Compliance risk

If you are required to have a monitored alarm (by an insurer, landlord, or regulation), a signalling failure could mean you are not meeting your obligations. Fire alarm communicators in commercial buildings have regulatory requirements. A broken signalling path is a compliance issue, not just an inconvenience.

Power-cut failure

If the alarm communicator now depends on the broadband router, it needs the router to have power. Most alarm panels have their own backup battery for the siren and sensors, but the communicator may need the router to send the signal to the ARC. A battery backup for the router can keep the signalling path open during short outages.

What to do

  1. Contact your alarm company (the installer or monitoring company, not the phone provider). Ask: "Our phone line is moving to digital voice. Is the communicator on our alarm system compatible? What is the upgrade path?"
  2. Ask for a signalling test after any change to your phone line. The alarm company should confirm that the ARC received a test signal correctly.
  3. Check your insurance requirements. If your policy requires a working monitored alarm, make sure the alarm company confirms in writing that the system is compliant after any changes.
  4. Consider a dual-path communicator. Modern alarm communicators can use both broadband and mobile (SIM) to reach the ARC. This is more resilient than relying on a single phone-line path.

Access control panels

Some access control systems (key fob, keypad, or card reader entry) have a dial-out feature that sends alerts over the phone line, for example when a door is forced open, when access is denied repeatedly, or when the system detects tampering. If the access control panel uses the phone line for these alerts, it is affected by the switch in the same way as an alarm communicator.

Contact your access control installer and ask whether the panel has a PSTN dial-out feature. If it does, ask about upgrading the communication path to IP or mobile.

Fire alarms: additional considerations

Fire alarm communicators in buildings with fire safety obligations (commercial premises, HMOs, care homes) are subject to regulatory standards. If the communicator path breaks, it is a fire safety compliance failure.

The responsible person (building owner, manager, or duty holder) should: