Product selection tutorial

Assembling a DCC decoder with Helvest products is very simple. Simply choose the necessary modules and insert them into the connectors.

For now, the available modules allow you to compose DCC decoders with different functions. Other modules with new functions will gradually be put on the market.

What do you need to assemble the DCC decoder?

1) HP100 motherboard

The HP100 is the “brain” that manages the whole system, so it is indispensable for any configuration.

2) Net module

The NET module handles communication with the digital control unit, the computer, or the rest of the layout.

Two protocols are currently available:

DCC: it is the traditional system, with which the layout is managed via the digital control unit. (DCC100 and DCC100-E modules)

MVnet: it is the innovative network developed by Helvest. This network is designed for two possible uses: to manage the layout with the computer or to manage automations autonomously, without a control unit.

The modules available are:

DCC 100

detects the DCC signal coming from your control unit.

With this module, the decoder is powered via DCC: i.e. you only connect the DCC wires to the HP100 and the decoder is ready.

Learn more about decoder power supply in this article!

DCC 100-E

detects the DCC signal coming from your control unit.

It reads just the DCC signal without drawing energy from it. The necessary power comes from a separate source: this is the recommended solution for larger layouts.

Learn more about decoder power supply in this article!


MV 100*

It connects your decoder or sensors to the MVnet network.
The MVnet network is bidirectional, i.e. it can receive and send instructions, whereas the DCC only receives commands without being able to send information.

* available from november 2023

These two parts (HP100 and Net module) are required for any configuration. You need to add one or two “layout” modules selected according to your needs.

3) Layout modules

On an HP100 board, you can insert only one Layout Module, or two identical modules, or two different modules. The wide versatility allows you to adapt to what you want to drive.
With two Layout Modules you can, for example, drive up to 8 different switches, or 4 switches and 4 signals. If you have fewer devices, you can drive only four using one module and save money.
The available modules are:


With this module you can detect the presence of trains in up to 4 sections by detecting current consumption. It detects trains on any power supply, either digital or analogue.

This module only works with the MVnet protocol (so it must be combined with the MV100 board).



With this module you can control up to 4 coils (also known as solenoids) to operate the turnouts. The solenoids must be suitable for digital operation (usually labelled as “low power consumption” or “DC operation”). This is the case for all modern solenoids on the market, from Roco* to Piko*, Fleischmann* to Peco* (but only PL-10W). If you have any doubts about your coils, please contact us.
The module is very powerful and requires no additional power elements: just connect your turnouts and you’re ready to go.


This module can drive up to:

  • 4 signals with red/green lights;
  • 2 signals with red/green/yellow lights;
  • 4 12V on/off lights;
  • 4 12V on/off motors (like a water pump, various animations, etc.)


This module can drive up to 4 turnout motors “with 3 wires”, i.e. with common anode and driven by a 12V DC current. Some examples are:

  • “MTB”* MP1
  • “MTB”* MP5


Connect this module to an HP100 in combination with one of the others on its side.
Connect up to 8 buttons to KB800. This allows you to control the accessories managed by the other module either via DCC or through buttons.


Like the KB800, it works in combination with any other module and a DCC module.
Accessories operated by the other module can be switched either by DCC or by pushbuttons. In addition, you can connect indicator lights to indicate the position of the accessory.


With this module you can control up to 4 servo motors. Servo motors were originally developed for model aircraft, but are also popular for moving points, level crossing barriers and much more on model railways. They all have the same operating voltage (5V) and the same connector, so this module can control all servo motors that comply with the standard norm.



This module can drive up to 4 turnout motors ”with two wires”, i.e. with polarity inversion. Some examples are:

  • “Conrad”* motors
  • “Fulgurex”* motors
  • “MTB”* MP5
  • “Tortoise”* and “Cobalt”* motors

* The names marked with an asterisk are trademarks of third parties and are the property of their respective owners

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