An accessory decoder that promises to control everything (turnouts, lights, signals…). I wanted to have a look!

This article is a about a product that does not seem to be manufactured/available anymore.


Qdecoder Z2-8+ in review

Qdecoder Z2-8+

Qdecoder is a rather young company. They started around 2009, and the team seems to be based both in Dresden (Germany) and in Switzerland.
They specialise in accessory and function decoders. There are different Qdecoder models, an overview of the product range is available on the Qdecoder website.

I have started to see some online comments on Qdecoder, which is how I heard about them. They also attend some model train fairs (including the important Nuremberg Toy Fair).

The Z2-8+ decoder

The Z2-8+ is the most universal model. It is designed to control pretty much everything:

  • Turnouts (with motors, double coils and single-coil)
  • Lights
  • Signals

Until now, we had to choose between many types of accessory decoders:

  • Decoders for standard magnetic turnouts (“magnetic devices accessory decoders”), for example turnouts form Fleischmann, Trix…
  • Decoders for single-coil magnetic turnouts (with only 2 wires), in N-Scale, mostly Kato and Tomix.
  • Decoders for motor based turnouts.
  • Decoders for lights or other “permanently on” devices (usually relay-based decoders).
  • Decoders for signals (recreating the advanced train signal combinations for one or several countries).

The Z2-8+ integrates the “signal add-on” functionality. Providing you configure the decoder well, it can simulate signals from many countries (Germany, Austria, Switzerland, Belgium…).
Have a look at the “Operating Modes of the Signal Add-on” document, it’s impressive! All those settings are usually made via changes to the CVs (Configuration Variables), with your DCC command station.
There are many other advanced possibilities: blinking, sequences, fade in/outs… Beware that all these configuration changes can be quite complex to implement.

But the Z2-8+ can also control “simple” devices such as turnouts. In such cases, you can configure the decoder as any other: by simply pressing the “programming” button and sending a command from your DCC system.
Even for this type of application, there are many options to use all outputs to the fullest. Take a look at the “Connections and operating modes of Z2-series decoder” document.


I ordered my Z2-8+ from Qdecoder directly (more on that later on). I received the decoder safely packed, with the printed manuals (which is very welcome):

Qdecoder Z2-8+ package

Qdecoder Z2-8+ package

The Q-Decoder is merely 6x4cm, that’s very small. It is an SMD-based electronic board, with a sticker hiding the electronic components:

Qdecoder Z2-8+ in review

Qdecoder Z2-8+ with size

The back of the decoder is fully flat and also covered by a sticker. This prevents short-circuits depending on where you mount it:

Qdecoder Z2-8+ back

Qdecoder Z2-8+ back

Test with my Kato turnouts

I wanted to replace a decoder that I wasn’t fully satisfied with, to control my Kato points. Although the Z2-8+ can control “only” 4 classic turnouts (for example from Fleischmann), it can control up to 8 single-coil or motor turnouts.

The Kato points are precisely single-coil turnouts, which means they only have 2 wires. Until now, I was using “regular” turnout decoders with small adapters. It worked, but it was taking a lot of space (and cables) under my layout.

Here is my short test report:

  • I set up the Z2-8+ temporarily under my layout. Connecting only the “DCC signal” and “power” connectors (one should not connect the turnouts immediately, since the decoder is pre-programmed for motor turnouts and might burn the coils).
  • I used the quick-programming mode: press the programming button on the decoder (LED goes on), send the appropriate command from the DCC system, and LED goes off to confirm. The setting I wanted was “250ms impulse, 8 turnouts attached, addresses 201 to 208”, so the simple command I had to send was: “201 green”.
  • I then connected my first Kato point: and it worked!
Qdecoder Z2-8+ in test position under my layout

Qdecoder Z2-8+ in test position under my layout

There is not much more to say. Programming took only a minute, and the decoder works reliably even when used with a PC program (sending quick sequences of turnout commands through the DCC system).

For me, the Z2-8+ has replaced 2 different accessory decoders, while occupying 1/5 of the space!
I have not tested the advanced signal options yet. If you want to check out how Qdecoders work with signals, you can check out the official Qdecoder Youtube channel with many videos.


Some people might complain about the lack of protective case. I like it that way: it saves space.
I have 2 comments however:

  • The documentation is excellent, but fragmented

Qdecoder has done a very good job documenting their products. Some of their manuals still lack an English version, but they are working on it I think. The documentation is extensive and well-written. Above all, it is well presented, in color, with a nice modern layout (many small train manufacturers should learn from them!).
However, because some functions are valid across several decoder models, you don’t get “one manual for all”, but rather many small leaflets. Same thing online: if you want information about Qdecoders, you will need to go the the download page and download 5 or more different files (after hunting them down…).
Because they have done such a great job writing the documentation, I think they should publish them in a more customer-friendly manner: just compile 1 manual for each decoder model, containing all the relevant information. Yes, it would be a hassle for them to update, but it would be better from a customer perspective.

Qdecoder Z2-8+ and its manuals

Qdecoder Z2-8+ and its manuals

  • No RailCom support

The Qdecoders support PoM (programming on the main). So you won’t have to unplug your modules to change the CVs. I would have appreciated support for RailCom programming, which also allows reliable reading of existing CVs.

But these are minor comments. As for the customer support (important for complex devices), I sent a question per email and got a very quick and friendly answer.

Pricing and target hobbyists

For standard applications such as turnouts, button-based quick programming should be enough.
The advanced configuration of signals via Configuration Variables, however, is not for the faint of heart.
 Therefore, if you are a beginner and want to control signals, you might want to look at more limited – but easier to use – signal decoders. Otherwise, Qdecoder also has a “programming service”.

For about €40, the Z2-8+ is in the same price range as the “single purpose” decoders. It’s actually cheaper for controlling 8 motor or single-coil turnouts (most decoders control 4 devices only).


I am quite enthusiastic about this product. This may well become my decoder of choice for the future.

The Qdecoder Z2-8+ is small, and can do almost anything. Most of my previous accessory decoders work well, but they all have only one purpose. This becomes a problem when you change/update/recycle your layout: you are left with decoders that may not match your future needs. With the Z2-8+, no problem: just reprogram the decoder for anything. The only thing the Z2-8+ cannot control: servo motors.

It feels good to see that relatively new companies can bring interesting products to the model train market, with a  modern & well executed approach (good documentation, Youtube channel…).

Have you tested the Z2-8+ or other Qdecoders? Do you know of any other “really universal” accessory decoder? Feel free to comment!

Final note on resellers & tips on payment method (edited Feb. 25th, 2014)

There is a small list of resellers on the Qdecoder website, I personally ordered mine directly on the Qdecoder online shop (also available in English) and received my decoder quickly. You can pay via wire transfer (a very common payment method in Germany), “one time” Direct Debit, and Paypal.
For anyone in the SEPA zone (EU and some other countries), doing a wire transfer is now relatively easy: they send you the invoice per email, you transfer the money, and wait. Most banks now allow to do this online. SEPA transfers are, by law, at the same price as national wire transfers…this means “free” for most banks/countries, but not for everyone: be sure to check out your bank’s pricing policy.
As for “one-off direct debits”, they are also very common in Germany, and are now possible within Europe with SEPA. It’s basically the same thing as paying your telephone bill (you provide your bank account’s BIC & IBAN), though of course you are debited only one time.
Qdecoder also lists one US-Based reseller, but I couldn’t find the Qdecoder products there.

External links

I always try to be fair and square when giving grades, see the details about the evaluation criteria here !

Reminder: I am a hobbyist and these articles only represent my personal views. I am not receiving any compensation, in any form, from the brands or stores mentioned here. The product names, marketing names, and brands mentioned here are the property of their respective owners.