Exam season is where most school bell systems get switched off entirely — which is the wrong answer, because the rest of the school still needs bells. What you actually want is surgical: this bell silent, that one moved, everything else untouched, and all of it back to normal on its own afterwards.
On an appliance, a schedule is a list of times in a box. There is no concept of "except in May". So the options are to reprogram the unit for the exam period and reprogram it back, or to pull the fuse and ring nothing for two weeks. Both happen, constantly, and the second is why staff end up shouting corridors clear by hand.
Software should handle this as a rule, not as a rewrite. There are three things you might need to change during exams, and one thing you should not.
An exam fortnight needs three things and rarely more: silence specific bells rather than all of them, apply the change only on the dates that matter, and have it revert on its own afterwards. Anything beyond that is usually a different day rather than a modified one. Each is expanded below.
The corridor bells next to the hall need to stop. The sports block, three hundred metres away, does not.
Bells choose their sound by folder, and a rule overlay can repoint an individual slot at a different folder on matching dates — including a folder containing a silent file. The rule carries filters: which slot, which weekdays, which months, which dates. First match wins, and if nothing matches, the ordinary timetable applies.
The important property is that the ordinary timetable is not edited. When the exam dates pass, the rule stops matching and normal service resumes with no second action.
Often the requirement is not silence but timing: clear the hall before the corridors fill. An offset rule shifts an individual slot's time on matching dates — the lunch bell ten minutes later for the exam fortnight, the rest of the day unchanged.
If your bells are accompanied by a spoken announcement, a text rule swaps the wording on matching days: "lunch is at 12:40 today" during exams, the usual line otherwise.
Do not build a second, parallel exam timetable and switch to it wholesale. It works for a fortnight and then drifts: someone changes a period time in the main timetable in October and nobody updates the exam copy, and the following May the bells are wrong in a way nobody can explain. Overlays exist so there is one timetable with exceptions, not two timetables.
There is a real exception. Study leave, an inset day, or the summer holiday is not "the normal day with three changes" — it is a different day, or no day at all.
For those, swap the configuration file instead. AlternateConfig pairs a filename with a date rule and switches at midnight:
<AlternateConfig>school-holiday.xml,20-07-2027|school-studyleave.xml,15-05-2027</AlternateConfig>A holiday configuration with an empty schedule rings nothing. Which file is currently live is displayed on the dashboard, so the office can see at a glance whether today is a normal day.
The rule of thumb: a handful of changed slots → overlay rules. A fundamentally different day → alternate configuration.
If the site has zone relays, exam handling gets better still: rather than silencing a bell everywhere, target the announcement at the zones that should hear it and let the relays mute the exam hall's zone for its duration. Two zones need a four-channel relay board; three or four need an eight-channel one.
Work through the list below several weeks before the first paper, not the night before. The two items that catch schools out every year are the dates arriving verbally rather than in writing, and nobody checking that the normal timetable comes back by itself once the exam window closes.
Try the live demo — see the schedule and rules in a working dashboard.
Can we silence bells only in the corridors near the exam hall?
Yes, in two ways: repoint those slots at a silent folder for the exam dates, or use zone relays to mute the exam hall's zone while the announcement plays elsewhere.
Will the normal timetable come back automatically?
Yes. Rules are matched per fire against the current date. Once the exam dates pass, they stop matching and the ordinary schedule applies with no further action.
What if exams clash with a shortened Wednesday?
Rules stack with the ordinary per-day schedule rather than replacing it, so Wednesday keeps its own times and the exam rule applies on top of them.
Do we need a different system for study leave?
No, but you should use a different mechanism: swap the whole configuration with AlternateConfig rather than writing dozens of overlay rules. A different kind of day deserves a different file.
Can the office see which schedule is live?
Yes. The active configuration filename is shown on the dashboard and in the console status view.
Part of the Multilarm automatic school bell system guide.