Smoke Compatability


New Member
What is the difference between S09A Smoke and S10A smoke?

I just purchased (4) GE TS7-2T 2-Wire detectors that I want to use on my Elk-M1 but I see that it requires S09A listing.
I have the installation sheets on the detectors but they indicate that they are to be wired in series with EOL resistor at end of chain and I believe Elk requires that 2-Wire smokes be wired in parallell.
On two wire smoke detectors, they are wired across the two wires (parallel wired) with an end of line resistor at the far end of the wire run. If any smoke detector shorts, the entire fire zone is shorted.

Burglar alarm, normally closed switches, are wired in series so that if any burglar switch opens the entire zone loop opens.