Siemens DCW20 Door chime with Entrotec Door Entry System

16 May 2020
Reaction score
United Kingdom
Hi everyone,

I live in an apartment block that has an old Entrotec door entry system. The standard Entrotec ED3 handset provided makes a horrific noise when someone buzzes in and I want to change it.

I am looking to buy off eBay an old Siemens DCW20 Door chime and connect it to the existing wiring.

The only thing I wish to achieve is to get the Siemens chime to "ring" when someone presses the Entrotec buzzer. As I live on the ground floor, I am not bothered about intercom and door unlock functions, so it is just the chime I want to replace.

Attached is a pic of the existing Entrotec handset and manual as well as the Siemens manual.

The question is, which of the existing cables will work for this purpose?
Is this compatible at all?

Any help is much appreciated.


  • Entrotec ED3.jpg
    Entrotec ED3.jpg
    202.8 KB · Views: 205
  • Siemens DCW20.pdf
    1.7 MB · Views: 731
  • ED3 manual.pdf
    1.4 MB · Views: 254
Sponsored Links
You'd do better screenshotting those documents or link to their original locations- I'm not a fan of downloading random pdfs.
But I was bored so looked up the originals.
You'll need a multimeter to determine what voltage the door comm is running at- the Siemens wants max 10 volt so if you've got more than that between VT and 0V you'll need a resistor in line.
You need to set the Siemens to Transformer mode (so connect to the T terminals)
The sounder signal comes off the ED3 EX terminal (8). Determine using your multimeter whether it goes positive relative to 0V or negative relative to VT when your flat is called (amost certainly positive relative to 0V but we all know what assume makes)
The sounder signal from the ED3 is pulsed which MAY trigger your Siemens thing many times. A capacitor will fix that, hopefully without annoying the ED3 too much. Try it without first
So most likely you'll be using 0V and EX (pins 3 and 8 ) to fire the Siemens. Bell wire or telecoms wire will do. And don't blame me if you break the whole door entry system.
thank you for your response, this is very helpful indeed.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links