More from Steve Redick on the Main Fire Alarm Office history:

This shows Ken Little hitting the master key on the amplifier panel that allowed him to send a signal over all the joker circuits at once.
 
Kenneth Little

Don Neal photo

Here are the two dispatching positions at the main panel with a microphone on each side. The master key is seen lower center. The little switches next to it allowed us to cut out certain circuits when transmitting. This was done when repeating certain signals we received from individual companies like out of service. All the switches between the microphones opened the circuit to each firehouse.  They were color coded. The black were single engine houses, red were single truck houses, and olive green were houses with both an engine and truck. We could open and talk to any number of houses at a time. On the right side we threw the switches up and on the left side we threw them down. That way both positions could be in use at the same time. The row of switches above the black area was to activate the simulcast where we could speak to every firehouse citywide or north side only. Above that a panel with counters and meters to monitor output. Above that were speakers including the Englewood talker circuit as well as a direct intercom with the same type of console at Englewood, simple, effective, efficient. 
vintage fire alarm dispatch setup

Don Neal photo

This image shows the satellite amplifier panel. This was extra and not used much It  operated the same way but had telephone style handsets rather than microphones. The yellow switches along the bottom were to allow us to use individual talker circuits. We would use this to send announcements to small groups for water shutdowns and the like. If you look closely you can see another master key to the right. The gray box above was a register to print out what was transmitted on the striking keys.

vintage fire alarm dispatch setup

Don Neal photo

 
I spent my early years on the job at the switchboard in the Main FAO. The red phone was hooked up to FI7-1313. The 911 call director is off to the left and not visible in the photo. The green phone is a call director with many lines, some direct and some regular IBT circuits. Front and center is the old cam operated switchboard. Red caps bottom row were incoming marshal lines, green caps in the middle were outgoing marshal lines and the top black caps were in and outgoing IBT lines. By placing the cams all the way in the down position you could link them with the other lines in that same column. The black dial phone is wired into the switchboard. The red phone is connected to the off camera 911 console. To the far right you can see the edge of the Motorola radio console. I spent many an hour at this position listening and learning my trade.
vintage fire alarm dispatch setup

Don Neal photo

This large panel had a light corresponding to every company in the city. As you might guess black for engines, red for trucks, black again for buggies, and red again for ambos. The only part of this I ever saw used were the middle rows indicating battalion chief status. The light was on if they were on the air and available. We controlled this by use of a large keyboard that took up a big chunk of the desk.
historic photo of the Chicago FD Main Fire Alarm Office located at City Hall

Don Neal photo

Ken Little in the Chicago FD Main Fire Alarm Office

Don Neal photo