GDX Intercom Testing

I’ve been looking for some… ANY device that would be compatible with a GDX intercom. Closest I’ve found so far is Nuki but looks like it’s not directly compatible with my system.

Although I don’t think it’s on the ‘Compatability’ list, I would be more than happy to test a Nuki Opener on my system.
This would certainly expand the list of compatible systems.
The country I’m from, this particular GDX system is the one that’s in most older buildings (mainly tower blocks, maisonettes circa 1950’s as it’s a cheap system to install and these buildings are usually owned by housing companies, not private or building investors.

I don’t know what model mine is but I’ve attached photos of the PCB. Maybe someone can shed some light on it?

What I do know is:
This was manufactured in 2010
The unit is an audio and video unit
There are 3 buttons on the front panel but one doesn’t do anything.

Hope that helps in some way.

Hi! Do you have a opener right now for testing?

Not yet because if it doesn’t work, then what? I’m stuck with some expensive kit that I can’t use.
I’d be more comfortable giving it a try if I could get some guidance on how to wire it to my current system etc.

For bus systems, you can just try, if it is not in the compatibility list, and for analogue systems it is two wires from the opener what shorts the two opening wires of the intercom when opening (what is the same what happens, when you push on the open button on the intercom), and two wires from the opener, where one wire is bell signal in the opener and one bell signal out of the opener, what makes a bypass of the bell signal over the opener, before it goes to the intercom, what gives the opener the ability to recognise and suppress (if wanted) the bell signal.

Edit: you can for testing just order a opener, and if it functions you can add up, and if not you can send it back.

One thing I do know is that the intercom doesn’t ‘function’ unless there is an initial call made from the outside control panel.
I’ve seen another post with an intercom that works on the same principle.

As I’ve got an unsupported intercom, is there any way to ‘break’ the Opener if the wiring is wrong or it doesn’t work?
Just want to know what I’m getting myself into before I start.
I’m not intending to cause any damage to your equipment but I just want to make sure I’m doing the right thing before I start.

Also, if I was to order an Opener, do I need any other equipment to go with it? E.G Bridge.


This activation before use is a known issue, for some it works for some not. The opener itself is pretty robust, - the most people (myself included) have testing their way to the right wiring, where often wires where not connected right when testing, and it never destroyed the opener, and I don’t heard about such damage. For the bridge, its not necessary but you loose some functions, like control from away, or Geofence actions like activation of ring to open when coming near home, but the most functions are there, and for testing you don’t need the bridge functions. - But if it works, I strongly suggest to add a bridge, and maybe some locks.