Upgrading from 2 wire to 4 wire Smoke Detectors

I just replaced a Vista 20P (with an Envisalink4) with Konnected and everything is working great. As part of this, I noted that my Smoke Detectors (3 of them) are 2 wire and thus not compatible with Konnected. They are older anyway and in need of replacement so I'm happy to replace them with 4 wire Smoke Detectors. The wiring run is 4 wire, so it shouldn't be too hard.

Per the recommendation on the Konnected site, I was going to replace them with the DSC FSA-410BST.

In reading the manuals for the DSC FSA-410BST it notes a few additional items that I'm not clear if I need for the Konnected install or not. Thanks in advance for any guidance.

1. It notes that an end of line resistor needs to be installed at the end of the series of smoke detectors. Do I need a resistor at the end of the signal wires with Konnected? If so, what resistance resistor?

2. Does an end of line power supervision relay need to be installed such as the DSC RM-2? Similarly, if an end of line relay was installed would it work and trigger the trouble alert if there were power issues?

3. The DSC FSA-410 manual noes that a Polarity reversing module (PRM-4W) needs to be installed to trigger all of the connected smoke detectors to sound if one goes off. Is this true with the Konnected setup? If I need a PRM-4W, how is it wired in?

 I can't figure this out either.  I have a single FSA-410.  When I connect Aux+, Aux- and then each side of signal, the alarm just goes off.    3 Beeps and a Pause, which is the normal pattern for Fire.

So I received my 3 DSC FSA-410BST late last week and installed them over the weekend. Install went smoothly. 

Of note, I did NOT install an End of Line Resistor, End of Line Power Supervision, nor a Polarity Reversing Module.

Testing all 3 by shorting the connection between the Common and NO wires correctly triggers the Zone in Konnected. 

Pressing the test button on all 3 of them triggers the Zone in Konnected and the Siren on the tested detector fires. The other 2 smoke detectors do not trigger and their sirens do not go off.

Of course, with the smoke detector triggering Konnected, I can trigger the other house sirens, etc.

One thing I had to do was change the Smoke Detector Zone setting from Normally Closed to Normally Open. Not sure if this will also help you Chris.

I'm still thinking about adding in the Polarity Reversing Module (PRM-4W) to see if it will trigger the other connected smoke detectors in the even of a fire. Not sure if I will need an EOLR and RM-2 to get it to work though. I'll update if I give it a try.

 I figured my issue out.  I actually had V polarity reversed.  I was following a tutorial and not reading the board labels.  I guess older Konnected boards had Aux+ and a shared Common with Siren, while my board has a Aux- and a shared + with siren.  I think alarm went off because reverse polarity is how chained alarms trigger each other.  Reversed the wires and all is good.

Snuffy2, Thank you for providing your experience. I am looking into this and you answered some of my questions. I wanted to be sure that you wired the way I think I need to. 

Are you wired to the Auxiliary NO and Common terminals or to the "Standard" terminals?

Are your detectors daisy chained or does each have its own home run of wire and individual pin assignment on your Konnected board?

I am interested in having all Detectors alarm, so If you manage to get that working I would love to hear your solution. 


Snuffy2, how did you define the FSA-410BST in your Konnected system, as a smoke detector or just as a open/close contact?

The FA-410BST doesn't have a normally closed terminal in it, so it shows open in my dashboard after defining it as open/close contact. If I define it as Smoke detector, then my Hubitat HSM cannot even show it in the list of things to trigger the alarm when away, night, etc.


I defined it as a Smoke Detector and then as Normally Open in the settings. I'm using SmartThings though so I'm not sure how that differs.