About the Smoke Signal:
The SS-200 is indeed exactly like the 79DCRI, in fact the covers are almost compatible — the 200’s cover can fit on the 79DCRI (though the test button offers resistance), but the 79DCRI’s cover catches are not cut the same as the SS-200’s, so they don’t quite mate with the -200.
•The “Sears” is a Lifesaver (mislabeled it, D’oh!) and is an F900D but the newer version with a piezo. They had this design before they switched to the compact version, like this Battery Operated Smoke Detector on Ceiling Stock Image - Image of danger, prevention: 12436003 About the horn: I was able to adjust the pitch on it by turning the horn itself, but the unit I currently have does not do that. Must have been a little quirk with that one alarm. I found this one by luck at the Missouri Council of the Blind Thrift Store in Kansas City. I heard a BEEP! while browsing the hardware section, so I dug through the stuff and found it. My aunt lived in the KC area and she was a thrifter also. Sadly she died in '97, I miss her so…
•The Ci-Toh used an 11.2 volt battery, basically a smaller version of the 12.6 volt one. Found that at a local thrift store.