Integrating Pacific 3404 4 Wired Door Intercom System

I recently moved into a condo that has a 4 wire intercom system to open the front gate and front common area door. The condo association isn’t interested in upgrading the system and the damn thing annoys the hell out of me. It’s so archaic, especially since the building is new and everything else in the place is fully automated. The in-unit control is a Pacific 3404 and uses the common 4 wires and has three buttons: Talk / Listen / Door. Additionally, the building also has a DVR system that I plan to integrate into Blue Iris, but that’s a project for another day.

Ideally, I would like to leverage SmartThings to buzz people in using my iPhone as well as a MagicMirror project that I’m building. Eventually, after I hook the cameras into Blue Iris and that into ST, it would send me the notification with the camera stream or a still image of the front gate.

In any case, I’m really surprised there’s not a “smart” type upgrade for this of system because I’ve seen these same systems in so many apartment / condo complexs in every major city. Like me, not everybody can put in a Ring or something similar - especially in the common area. It’s an untapped US market. The closest thing that I’ve come across are the Nello One and Klevio - both of which are only the in the EU. Likewise, there’s tons of posts here and other forums from people looking to do the same thing.

One in particular written by Chris Whong appears to be the most promising: Connecting an Apartment Door Buzzer to a Smarthome Hub | by Chris Whong | Medium. Unfortunately, I’m really light on the electronics knowledge, but I want to give this project a try and I’m having trouble finding the relay that he used. It’s just not manufactured anymore. I have his code on Git (GitHub - chriswhong/mimolite-door-buzzer: SmartThings Custom Device Handler for MIMOlite connected to an apartment intercom) and I’m ready to pull the trigger on the MIMOlite. (

Option 1 - I find a replacement for the RY014B. I’ve done some digging and the board was primarily used for hooking up an external signaling device like a strobe or flasher to the intercom. I did come across some possible alternatives. . Would any of these work? Any alternatives? Cheaper?

Option 2 - I make it myself. I mean, I can solder and if given a parts list, source and some simple instructions, I probably can make the board (When I was like 10, I recall making a light pen for my Commodore 64 from a guide in PC Mag, so I do have some skills). Although it’s a very simple circuit, I just have no idea how to read schematic and translate it into parts.

I’m not 100% committed to Chris’ approach, but again, seems like the easiest provided I can find a replacement for the relay. If anybody has a better way of achieving my integration goal, I’m open to considering it. Which every approach works, I most definitely will post a guide here.

Not necessarily better, but another option is to use a “robot finger“ to just push the door button. It’s just a question of how much force the button requires. I used to use the Naran Prota Microbot for these kinds of use cases, but I no longer recommend it. So right now in US about the only widely available option is the SwitchBot, and it can only handle a force of about 1.5 kg. that will work for a lot of buttons, but not all. Integration with smartthings is available cloud to cloud or via Matter with their Hub 2.

Here’s my 2019 review (The topic title is a clickable link)

You might have to use Sugru to get it positioned just right.

I agree the board solution would be better, but this is just another option. :sunglasses:

I appreciate the response and information, but I want to stay away from mechanical type of solutions and want to completely replace the call box or at least hide it behind the MagicMirror that I’m building.

I also want to be notified and be able to buzz in package deliveries when I’m not home. I think I’ll be solid if I can just find a replacement for that relay


Tagging @ogiewon

So can anybody simplify this very simple circuit into a parts list or have recommendations for a replacement?

@kbuchaniec Did you ever get this working? I have a particle photon connected to the unlock button to trigger remotely, but haven’t yet incorporated voltage sensing the buzzer

I can’t believe that two years have passed and nobody was able to decipher this diagram for you. It doesn’t seem it’d be too difficult for someone with the basic skill set.

I’m here to also replace my dumb Pacific 3404 :joy:

In my situation it’s a 3 unit condo (3 levels) and prefer to keep the main call box as-is — just simply replace the intercom + buttons with something more intuitive for just my unit’s call/intercom box.

Bonus points would be to integrate the stream I have from a Unifi camera pointed outside.