I’m bumping just like Fire alarms are cool is, but the revamped version of de_nuke in Counter-Strike: Global Offensive has a fire alarm system.
The pull stations are based DIRECTLY off Fire-Lite BG-12Ls, even having the original “Fire-Lite” logos intact, however the “FIRE ALARM” lettering on the top is taken from the Simplex t-bar. There are both flush and surface mount versions, and covers for each type. Quite surprised Valve hasn’t been sued by Fire-Lite for unauthorized use of their logo, though I guess Valve decided to leave the logo on the model due to it being a small detail in the map that probably few players would notice.
The actual alarm models in the map are based off the alarm models from Left 4 Dead 2 (Wheelock MT/LSM), albeit with no “FIRE” lettering on the sides and white so they can be painted any color.
The smoke detector models are pulled straight from L4D2 (Simplex “wiffle ball” detectors).
No panel can be seen, though I’m sure Valve knew it wouldn’t be worth the time and expense to make a model and place it in the map as chances are again players simply wouldn’t notice it in the heat of battle.