Today's locomotive decoders offer the model railroader many possibilities to adjust their behaviour to the individual conditions on the model railway and the wishes of the operator.

Decoders are an electronic component for decoding digital signals. They convert control commands, for example, into concrete travel commands for the drives. In digital operation, the travel and switching commands are transmitted from the control unit to the locomotive via the track. Very important: When delivered, the decoders are already optimally adjusted to the corresponding locomotives. Before you change values, you should have an overview of the effects of your changes and only make changes if you are technically experienced.

• In the following, we always assume the use of a decoder of the mLD3/mSD3 generation. For other decoders, either not all entries are available or other register addresses must be used.
   
• Important: Since in extreme cases programming the wrong register can lead to this decoder becoming unusable, it must be clarified beforehand which decoder it is.
   
• A project from Decoder Tool 3 is the new basic project for this decoder after the installation. After a decoder reset, exactly these settings are effective again. Changes made with a CS3, for example, are also reset to the basic values after a decoder reset. Therefore, one should plan these projects very carefully so that as few changes as possible are necessary later.
   
• The Decoder Tool 3 is designed for programming retrofit decoders and is not suitable for changing series decoders. Series models are tuned by Trix specialists and can be edited with a CS2 or CS3, for example. A decoder reset restores the series condition.
   
• With the Decoder Tool 3 you can access a constantly growing number of decoder projects of the series products. If these projects correspond to your wishes, you can load them directly onto the retrofit decoder. Otherwise, you adapt a project to your wishes and then play it onto your decoder.
   
• Registers can either be programmed with values of a certain value range - for example from 0 to 255 (0 usually stands for minimum, while the highest value stands for the maximum setting). With other registers, different possibilities can be switched on or off. Up to 8 bits are available for this purpose. If a certain bit is to be set, this is generated by a certain value that only this bit has (bit 0: 1, bit 1: 2, bit 2: 4, bit 3: 8, bit 4: 16, bit 5: 32, bit 6: 64, bit 7: 128). All unused bits are always set to 0. The value in the register is the sum of the bits. Example: Bit 1, 2 and 4 are to be set: This results in a value of 2 + 4 + 16 = 22.
   
• If such a register is programmed via the CS2 or CS3, then a selection field is displayed in mfx mode, in which the bits only have to be marked. This is what makes mfx programming so convenient, as you do not have to worry about the individual values behind it. The system automatically adopts the correct value.
   
• Of course, this also applies to the Decoder Tool 3, where there are corresponding selection windows for many settings. You do not have to check which value is programmed in which register (CV). The system does this automatically for you.
   

Of course, it is great that the decoders can handle so many formats, but sometimes these possibilities also conflict with each other. For example, if you work on a layout with reverse-pole DC voltage in the braking section, the analogue DC operating mode can lead to undesired operating behaviour. Therefore, you should always switch off all operating modes that you do not need. At least one digital operating mode must be set up, otherwise a decoder would no longer be reactivatable. Therefore, the operating mode via which the decoder is currently programmed cannot be deactivated.

When programming via a CS2 or CS3, it is determined in the configuration menu of the decoder which other operating modes the decoder should observe. This is done in the menu item Formats. But in this menu the operating mode mfx cannot be deactivated. To do this, the mfx format must first be switched off in the CS. Then the mfx capability can be deactivated in the locomotive decoder under DCC.

The values for all operating modes that are still possible except DCC are simply added. Thereby the values for CV 50 are under DCC:

Bit 0: Analogue AC voltage off/on => 0 or 1
Bit 1: Analogue DC voltage off/on => 0 or 2
Bit 2: Digital MM/MM2 off/on => 0 or 4
Bit 3: Digital mfx off/on => 0 or 8

If the model is to handle analogue AC and the MM format in addition to DCC, this results in a value of 1 + 4 = 5, which is programmed into CV 50. All operating modes are set as standard, which results in the value 1 + 2 + 4 + 8 = 15. With the Decoder Tool 3 you can already deactivate the unwanted formats in the basic configuration. Later, these can be reactivated by programming, for example via a CS3.

Consider which operating modes you definitely need. Only these formats should be activated in the decoder. Note: Protocols that are switched off can also be switched on again later with the appropriate programming tools. Therefore, operating modes that are deactivated with Decoder Tool 3 on a retrofit decoder can also be reactivated with the appropriate mfx, MM2 or DCC programming.