Not with a 2GIG system. The only compatible system that you can currently connect wired smoke detectors to is an Interlogix/GE Concord 4. For smoke detectors, 2GIG only works with 2GIG, Honeywell and System Sensor 345MHz wireless smoke detectors.

what about the other two questions

I’ll answer

N0 to existing hardwired 120v smoke alarms. Electrical code prohibits it. You can’t run high voltage/low voltage in same box.

In my case, I have 9 smoke alarms/detectors-
6 are interconnected 120v ion/co smoke alarms on each level, and in all bedrooms. On each level (3) I also have 2GIG photo/heat detectors.

Most fires in a home occur when you are sleeping, and are the smoldering type (detected by photo detectors)

As for siren in attic. Why not go a zwave/wireless 100db siren that you can get for $29 at Lowes? Easy to mount, runs on batteries…


For an external siren you can either wire it to the back of the 2GIG control panel or use a z-wave siren as suggested above. Do you have a preference? If you use the battery powered z-wave siren then no, you don’t need a backup battery. If you use a wired siren then you don’t need a battery backup because the 2GIG panel’s backup battery will keep it going, but that will use up your 2GIG’s backup battery faster. If you’re siren is powered by wall power and you want it to keep working when the power is out then yes, you’ll need to add a backup battery.

Kidde SM120X designed specifically for this purpose.
I guess you will have to use dry contacts in 2gig panel and program it as smoke/fire detector.

The Kidde SM120X should technically work with 2GIG.

I’m not sure about the UL listing implications of doing that though. 2GIG doesn’t support it. You’re insurance company might not consider it kosher.

The 2GIG panel has 2 wired inputs on the back of the panel that can be programmed as normally open or normally closed.

In Chicago and suburbs wireless smoke detectors are not considered kosher ether.
Only Hardwired-Interconnected-with battery backup, one in every bedroom, one CO/smoke per floor and within 15ft of bedrooms (so could be more than one if hallway is long), one CO/smoke in mechanical room. 2 bedroom townhouse usually has 5-6 detector. Imagine customer frustration if couple more has to be installed for alarm system.
Fire Inspector on our last job site(residential) gave us permission to use one of these Kiddie SM120X and CO120X or RM4 BRK.
In my opinion 2gig Smoke/carbon detectors should be looked at as a bonus feature, because they are dependent on control panel being operational and cannot trigger other detectors in case of communication failure.
I guess one of the reasons 2gig does not allow smoke detectors on hardwired loops, because connection and status of detectors cannot be supervised

Keep in mind that if a location has interconnected hardwired AC smokes, you wouldn’t need to double up on detectors. A Firefighter audio detector will make use of those existing smokes.

Looks promising, will try it next time.
I wonder why 2gig don’t make hardwired detectors, since they already have wireless unit it shouldn’t be a big deal to modify.
Every new house must have it and also must replace them every 5 years… never ending business unlike sensors and panels $$$

Likely a combination of reasons. A couple off the top of my head that i would guess: Wireless devices are likely viewed as more desirable. Also the power requirements to run low voltage wired smokes would probably require a hardware change to the panel design.

The requirement for hard-wired smoke detectors with battery backup is a national fire/building code requirement. That’s enforced in almost the entire country for new builds or renovations.

The insurance company issue I’m warning about is different. If your house burns down the insurance company might do an investigation. If you have a monitored smoke alarm system and were getting a discounted insurance rate because if it then the insurance investigator might inspect your alarm equipment. If they find that you were using something that’s not tested and approved by UL or ETL then they might deny your claim because you didn’t have an approved set up. 2GIG doesn’t test or support monitoring hardwired smokes as far as I’m aware so you might be leaving yourself open to risk if you monitor wired smokes with a SM120X and a 2GIG panel. It should still technically work. In the past, every time I’ve asked 2GIG if I can do this or do that with wired smoke detectors their response was to only use approved wireless smoke detectors. The Encore Controls FireFighter cleverly works around that problem.

The real motivation behind this might just be that 2GIG wants to make money selling you wireless smoke detectors. Encore Controls is owned by Lance Dean, one of the 2GIG founders, so maybe that’s why they’re OK with it? Who knows… All I know is that I have been warned repeatedly about tinkering with unapproved smoke detector configurations.

So anyone wonder like me why not just make a wireless smoke detector that simply PLUGS INTO the interconnect power/bus to detect the rest? Not only could the detector extend battery life but seems like a cleaner solution then having an “audio gap” like the Encore. Is the interconnect between hardwire-only detectors proprietary or something?

If it physically touches UL/ETL tested smoke detectors then it invalidates their certification. The audio/air gap is a clever trick so that a single low cost device can monitor all kinds of smoke detectors without having to be certified with each and every one of those models. All certified smoke alarms are required to use a specific sound pattern so the audio is actually the most standard interface to integrate with.

You’re right about it being more efficient to just wire to them but the cost integrating and getting certified with all different smoke detectors is much higher.