A bell controller is a clock and a list of times, and the list is password protected and it prints. Ours has an entry at fifteen forty two that I did not make, that I cannot delete, and that closes the relay whether or not there is a bell on the end of it.
I am the site manager at a secondary school with eleven hundred pupils. Nineteen years.
The system, because it is simpler than people think.
There is a controller in a cupboard in the main corridor. It keeps time, it holds a programme of events, and each event closes a relay for a set number of seconds. The relay puts twenty four volts down a pair of wires to the sounders, of which we have thirty one.
The programme is a list. Start of day, lessons, two breaks, lunch in two sittings, end of day, and the fire test on a Wednesday morning. Thirty four events. It is protected by a four digit code that three of us know, and the thing prints the programme to a little thermal roll if you ask it to, which is how I audit it at the start of every term.
There is an event at fifteen forty two.
Three seconds. Every weekday. It is not on any programme I have ever made and it was on the roll the first time I printed one, in 2007, before I had changed anything.
School ends at fifteen fifteen. By twenty to four the building has about forty people in it.
What I have done to it.
Deleted it. It deletes. The display confirms, the roll prints without it, and it is back on the roll the next time I print, which is usually a week later because I am not in that cupboard daily.
Changed the code. Twice, once to something only I knew.
Replaced the controller, which should have ended it. New unit, different manufacturer, installed by the fire and security contractor in 2014, programmed from blank by the engineer with me standing there, thirty four events entered by his hand.
It was on the roll in March.
What I measured, which took me seven years to think of doing.
I put a multimeter across the output terminals with the bell circuit disconnected at the controller end.
At fifteen forty two it reads twenty four volts for three seconds.
I have done that on eleven occasions and it has read twenty four volts on all eleven, and on one of them the controller was not showing an event at all, because I had deleted it that morning.
What it sounds like.
Nothing, if the circuit is disconnected, which is the only reason I learned to live with it.
With the circuit connected it is a bell. A three second bell at twenty to four, and nobody has ever remarked on it, because a school makes noise and the people left in the building at that time are cleaners and a caretaker and two or three staff in their own rooms.
I asked once, in 2011, casually, in the staff room. One teacher said she thought it was the cleaners' bell. There is no cleaners' bell.
What I cannot put in a report.
Fifteen forty two is not a school time. Nothing in this building has ever happened at twenty to four.
I went looking in the county archive, because my predecessor's predecessor kept the site log and it went into the record office when the old block came down.
This site was a different school until 1974, and before that a different one again, and the logs are a page a week of weather and absences and deliveries.
There is nothing in them at twenty to four.
So I have no story to tell you about why that time, and that gap matters, because every version of this I have heard off anybody else comes with a date and a name attached and mine does not.
What I have is a relay that closes when there is nothing on the other end of the wire to tell it to.
What I do about it.
The event stays on the programme now. I put it back myself after the engineer in 2014, as a regular event, three seconds, so that anybody printing the roll sees thirty five events and nothing odd.
I moved the sounder out of the corridor by the gym. That one is right outside a classroom that is used for after school revision on four nights a week, and a bell three seconds long at twenty to four in a room of fifteen year olds trying to work is a distraction they do not need.
And I do the cupboard in the morning now. Anything that needs doing in that cupboard, I do it between seven and eight, with the lights on and the corridor full of nobody, and I am out of it by nine.
I stood in there once at twenty to four, in 2016, with the door open and the meter in my hand and the bells live, to see whether the relay makes a noise when it closes.
It does. You can hear it click about half a second before the bells go, which is the contactor, and it is the most ordinary sound in the world.
What I did not expect is that the thing in that cupboard is at chest height, and when it clicked I found I had already stepped back into the corridor, which is not a decision I remember making.