2-wire smoke detectors

Hey all-

I have been working on a 12-zone conversion from my old Ademco panel that has been inactive for years.  On zone 1 the smoke detectors are connected with a black and red wire. These are tied into multiple other 2 wire and 4 wire bundles to chain up 11 smoke detectors throughout the house. All of the smoke detectors are System Sensor 2100TS. They appear to be 2-wire smoke detectors. 

Is there any way I can power these smoke detectors without retaining my ademco panel? 

Is there anyway to convert these detectors (using the same wiring) to work with Konnected?

The detectors are surely over 10 yrs old, so I will likely replace them anyway. The question is can I replace with a similar upgraded version and keep using original wiring? The advantage being aesthetics and not having to change batteries. 

My last thought was just replacing all with battery powered first alert detectors - which will do the job but not as slick as low voltage wired detectors. 

Thanks in advance-


Did Lee get an answer for this question about the 2-wire smoke detectors?  I have the same question and am looking for a 2-wire smoke detector module


Coming to revive this. Glad someone explained exactly what i see. The old transformer which dummy me threw away but at least i have pictures was wired to zone one with a blue and yellow wire. Then smokes is a 2 wire run from another zone. I’m not sure how i’m supposed to power the smoke detectors.

Old thread but still a relevant question!

The short answer is – two-wire smoke detectors do not work with Konnected. Please reference this KB doc (and the linked pages) for complete information: Smoke & Carbon Monoxide Detectors

Two-wire smoke alarms from traditional alarm panels require 12V power over the two wires and employ a special “polarity reversal” mechanism where the smoke detectors reverse the polarity of the power to the detector to signal an alarm. This will NOT work when wired to Konnected, and will likely cause a short circuit and damage to the board.

We recommend that you replace the 2-wire smoke detectors with 4-wire models that have a separate pair for power and signal. Another option is the System Sensor COSMOD2W which is like an interface to the 2-wire smoke detectors that powers them and provides separate output zones for Smoke and CO that can be wired to a zone on the Konnected Alarm Panel.