First Alert connection

I have a new house construction with First Alert smoke and CO2 detectors all connected together.  I bought the RM4 Relay (see link below) this from Amazon as directed from a Konnect page on smoke alarms.  The wires that come off the relay are power, always on, always off.  How do I connect this to a Konnected device?

Hi Ken, 

I've attached a  copy of the RM4 Relay data sheet which has instructions for connecting the relay into your existing home's smoke alarms.

Wiring To Existing Smoke Detector Wiring: 

Basically the White, Orange and Black wires on the relay need to be connected to your existing alarms wiring. (White to White), (Orange to Orange) and (Black to Black). NOTE: The White (neutral) and Black (Hot) wires are 120VAC on your existing homes system.  ALSO: The relay should be installed in an approved electrical box to be compliant with electrical codes. 

Wiring To Konnected Device: 

The relays Blue, Brown and Gray wires are used to trigger the Konnected device. Typically you would use the Brown wire from the relay to connect to a Ground connection on the Konnected device. Then the Normally Open (NO) Blue wire would be connected to one of the Zones you select on the Konnected device. You would then setup the Konnected smart app to monitor the zone you selected as a Smoke Detector. 



Thanks Greg!

I was on another thread that asked the same question, I think this answers both! 

I'm going to try it out and will report back.

All hooked up and working!


Great, I’m glad it’s all working and its always satisfying to have it finished and working. I assume you’ve tested it using one of the with the Konnected zones. I’ve implemented a similar configuration on my smoke alarms. As a final stress test I’ve cut the 120vac power to the smoke alarm and depressed the test button yo see if the 9v backup battery in the alarm will trigger the Konnected zone and it does. So I have confidence that even in the event of a fire and the house power goes out the Konnected system will work. Which also means having a backup battery for your Konnected board and siren / strobe should be considered to complete the system.

Thanks Greg,

Yep, I tested it, but my system only works with 120VAC. The alarms work on the 9V, but don’t activate the relay. While it would be good to have monitoring when the power is out, I’m happy to at least have it monitored the majority of the time.

I do have a UPS powering my modem/router, the ST hub and Konnected boards.

The next project will be the back up data connection, looking at the Netgear LB2120.

What do I do with the gray wire from the relay?  Do I just leave it not connected to anything?  Also, what is the best place to install the relay?  Do I connect the relay directly to the Konnected board and then run romex to the nearest smoke detector?

I left the grey wire unconnected, but I crimped off the end to make sure it would not contact with anything. I put the relay inside the alarm housing, then ran the wiring from the relay to the connected board. I used normal security system wiring, I think mine is 18 or 20 gauge.

 @Greg: Where did you find a relay that will operate without 120v power? I used this relay that was recommended by the Konnected website:

But I've found this relay will not operate if I cut the 120v power.


I reviewed the relay on the link you provided ( and it requires 120 Volts AC to operate.

In my configuration I elected to use a 5 volt DC power and Ground pins on the Konnected board as the power source for a 5 volt DC relay rather then a 120 volt relay. Either will work it was just a matter of preference and I had a 5 volt DC relay avsilsble.



Attached is a diagram showing the details of my smoke alarm integration with the a Konnected NodeMCU board. Hope this helps. 


How does the hard wired signal from first alert CO and fire discriminate between the two signals? Does it just say CO OR FIRE?


In my configuration the alarm does NOT have any ability to discriminate between the fire and smoke. It only has ONE signal from the alarm connected to the 5VDC relay IN terminal. This single signal on the IN terminal is activated when the alarm senses smoke or CO no distinction is made to separate the two. I can only speak to my configuration which I've documented in the attached configuration file. NOTE: Only one signal activate signal is connected to the 5VDC relay. The other signal is a 5VDC ground signal needed to and a ground reference for the circuit. 

Thank you very much.  I'll just have to separate them.  Thanks again.

Your Konnected device should be able to detect when incredibox the First Alert smoke and CO2 detectors are triggered and take the appropriate action, such as sending a notification to your smartphone or triggering an alarm.

Thank you for the information. Just to clarify, when connecting the relay to the Konnected device, should the Gray wire be connected to the power supply of the Konnected device or to a different connection?