The NJH Campus in Denver, CO has some interesting buildings and equally interesting Fire alarm systems. Some of the photos have been cropped and or blurred due to sensitivity. All of the systems are tied together into a single office. Here are some of the photos of the old fire alarm systems. Some of the ceilings are very low, so the N/A's were very low, and against code.
A 2902-9739 and 4251-30 GA, but the GA key switch was removed. Low ceilings!
Unusual Combination of a 2901-9833 and a 4903-9101.
Chemtronics Heat Detector at the top of a stairwell
2903 series A/V with a generic speaker!?!?
2901-9838

Simplex 2001 panel, I think, it might be a 4207 or somthing. no march time card :(
Large 4002 system, has 9833's and whiffleball detectors.
Very poor install of 2902-9739 and 4251-30 about 4 feet high. No wonder this was in an old utility room; it would never pass inspection. Sorry about bad photo-couldn't find a light switch

"Whiffleball" smoke detector
2901-9833
4251-30 with GA key switch removed-closeup