What is a Joker Box?
The box was connected to a telegraph wire that went to every fire station in the city. Inside each box was a spring-loaded wheel with bumps on it. The bumps corresponded to the number given to the box. For instance, if the box’s number was #123, the wheel would have one bump, then two bumps, and then three. When someone pulled the handle located outside the box, it released the spring-loaded wheel, causing it to turn. The bumps pressed down on a key, sending an electrical signal to every fire station in the city. In the stations, a bell would ring out the number of the box. At the same time, it punched holes in a paper tape at the watch desk. Fire companies assigned to this particular box would dispatch themselves to the fire. What’s most interesting is that every fire station in the city had to keep track of every other fire station—just in case the station that was assigned to that box had already been called to another fire. Interestingly, telegraph alarm boxes were widespread throughout the 1920s, 30s, 40s and 50s, and in some cities, they were still being used during the 1960s and 70s.
How did the box get reset after the fire? Well, the fire chief, of course. He simply used a key to open the box, rewound the spring—and the system was ready to go once again.
All Tapped Out?
Here’s a bit of trivia you may not know: When the fire was finally under control and the fire chief returned to reset the box, he would “tap out” a signal indicating that the box was clear because the fire was now out. In many cities the code for under control was “1-1” and the code for all companies clear was “6-6”. Fire personnel at the various stations waited to hear that the fire was “tapped out.”
The photograph is from the Fire Museum of Maryland.