In short
In an emergency your screens are the fastest way to reach everyone at once, but only if the message can be triggered in seconds by the people on site. PlainSignage's emergency override takes over every screen of the account instantly with a title, message, colour and optional siren, from the console or with one API call from a fire panel or building system, and clears itself after a set number of minutes. This guide covers setup, the API, sounds, roles and drills.
What an alert screen must do
Fire, gas leak, lockdown, severe weather, a missing child in a shopping centre: the message is different every time, but the requirements are the same. It must reach every screen at once, including the menu board in the café and the timetable in the hallway. It must be unmistakable — full screen, high-contrast colour, large text, ideally a sound — and it must not depend on someone finding the right playlist in a hurry. Afterwards it must go away cleanly so normal content resumes.
Screens complement, never replace, the certified alarm system: they add the words (“Exit via the east stairs, not the lift”) that a siren cannot.
The emergency override
In the PlainSignage console, Alerts → Emergency override lets you type a title and message, pick a colour (red for evacuation, blue for lockdown, amber for a warning), choose a sound and set an auto-clear time. Press Activate and every paired screen of the account switches to the alert within a second, on top of whatever it was playing — playlists, layouts, games. Screens that are asleep under their screen hours wake up for it. Press Clear and everything resumes where it was.
Prepare the three or four messages you might need in advance so nobody has to write under stress; in an emergency you pick one and press the button.
- Full-screen takeover on every screen, in under a second
- Title, message, background colour, optional sound (siren, alarm, chime or your own audio file)
- Auto-clear after n minutes, or clear manually
- Works on Android TV, Fire TV, tablets and the browser player alike
Trigger it automatically with the API
Buildings with a fire panel, an access-control system or a building-management platform can trigger the same override without anyone touching the console. Create an account API key with the alerts scope and send one request:
POST https://console.plainsignage.com/api/v1/alerts with a JSON body such as {"title":"Evacuate","message":"Leave the building by the nearest exit. Do not use the lifts.","color":"#c8102e","minutes":30,"sound":"siren"}. A DELETE to the same URL clears it; GET returns the current state. Tools like Node-RED, Home Assistant, Zapier or a relay board with an HTTP client can call it from a dry contact on the fire panel. The full reference is in the developer docs.
Sounds and silent alerts
Choose siren for evacuation, alarm for lockdown and chime for informational warnings — or upload your own recorded announcement to the media library and select it; it loops on every screen with a speaker. For a lockdown you may prefer a silent alert with a blue screen and a calm text, so the screens do not reveal to an intruder that the building has been warned. Test volume on each screen once; TVs remember it.
Single-screen notices for smaller situations
Not everything is an emergency. A delivery at the back door, a spill in aisle 3 or “the 14:00 meeting moved to room B” fits a notice: a banner on one screen for a set number of seconds, sent from the console or via POST /api/v1/notice with a screen key. Notices do not interrupt the content and disappear by themselves, which keeps the emergency override reserved for real alerts.
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Run a drill every quarter
Practise the same way you practise the alarm: pick a quiet moment, announce a test, activate the override with a “TEST — no action required” title, walk the building and check every screen, including the ones in stock rooms and corridors, then clear it. Note any screen that did not switch — usually one that was unplugged — and fix it. Five minutes, four times a year, and the day it matters everyone already knows what the screens will do.
Everything above is included in the single plan, alongside menus, dashboards and guest games: see features and pricing.
Frequently asked questions
How fast does the alert reach the screens?
Within about a second on connected screens; the player receives a push over its live connection and switches immediately. Screens in sleep mode wake up for the alert.
What if a screen is offline?
An offline screen cannot receive the alert; it keeps playing cached content. The console's screen list shows which screens are online, and offline emails warn you when one drops off, so you can fix it before it matters.
Can I trigger the alert from a fire panel or building system?
Yes. Any system that can send an HTTP request can call the alerts API with an account key that has the alerts scope. Node-RED, Home Assistant and most building-management platforms can do this.
Does the alert play a sound?
Optionally: siren, alarm, chime or your own audio file, looped on every screen with speakers. You can also run a silent alert for lockdown situations.
Does the override replace our alarm system?
No. It complements the certified alarm by adding clear instructions on every screen. Keep the alarm system as the primary, regulated warning.