So, this summer I'm attending a programming course (DO NOT ASK for more details) at Harvard University in Cambridge, MA. (but not this upcoming week, thanks to something which you'll be able to figure out from my next post.)
Here are the fire alarm systems at Harvard I've seen so far...
Gutman Conference Center
Panel: Simplex 4100 (there's an annunciator at the entrance)

Pull stations: 4099-9001's, and 4099-9006's in renovated areas.

Detectors: Newer TrueAlarms

Signals: TrueAlert speaker/strobes

There are also many Edwards Adaptahorns, which are now obviously disconnected.

53 Church Street
Panel: FCI FC-72, located at the entrance
Pull stations: Sigcom SG-32's rebranded by Mammoth Fire Alarms

Detectors: Fenwal PSD-7155's (?)

Signals: Gentex Commander 2 horn/strobes

Also, something happened on Wednesday... (drumroll, please!)
I was walking near Porter Square (also in Cambridge) when I heard something beeping. I first thought it was a timer in a restaurant, but then I noticed it was in code-3! So I went to investigate.
It was SpectrAlert Classics, at a multi-family home. (I could also hear what sounded like mini-horns in the background.)
When I got there, someone who looked like a manager had just arrived and was on the phone with someone for a few minutes, and then silenced the alarm. (Didn't see the panel, but it kept chirping every few seconds once silenced.)