Receiving Board for a Municipal Fire System

This receiving board was designed in 1895 and went into service in 1901. It operates off of 600 volts of DC electricity, and was once powered by streetcars. The streetcars only ran from 5am–1am, so during the day the board charged batteries that kept it powered through the night.

The tubes along the top of the board correspond to each of the circuits that reported to the board. Each number inside the tube corresponds to the municipal telegraph fire boxes (see Municipal Fire Box) that were on that circuit. Big cities would have dozens of boxes on each circuit.

In the event of a fire, someone on the street would pull the lever inside of a nearby municipal fire box. This would send a telegraph signal to the receiving board. The light under the circuit that the box was on would flash the number of the box (four flashes, a pause, and then one more flash for Box 41). The number of the box would also print out below. This process would repeat more than once in case multiple boxes were pulled at the same time, to ensure that no one signal overrode another. After determining which fire box was pulled, the operator would then use the telegraph switches to retransmit the alarm to the fire station closest to the box’s location.

Along with the firefighters, a Communications Officer from the fire department would arrive on scene. They would use a button inside of the municipal fire box to tell the fire headquarters that they were there. They would also assess the size of the fire, determine if more engines were needed to fight it, and request them by using that same button to essentially set off the alarm again. This is where the terms “one alarm fire,” “two alarm fire,” and “three alarm fire” come from. If the fire was big enough and dangerous enough, multiple alarms would be set off by the communications officer.