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The LoDi-KSM

Why do you need a reversing loop module on a model railway system? 


In principle, reversing loop modules are only required for the 2-wire system. 


The reverse loop module switches a reverse loop automatically.

A reversing loop occurs, as you can see in the picture, when the power supply is crossed when the train drives backwards or turns in a circular section when it enters the track again.

Here you can now see that the red line crosses the stream over the blue line.

This is then called a loop.

In order to avoid a short circuit here, you need a  special switch or relay that reverses the polarity of the supply voltage of the track in the reverse loop.

You can see how you use the device by scrolling down. 



The properties of the LoDi-KSM(-P)


  • Reversing loop module (KSM) for your digital model railway and track sizes from Z to G.
  • The reverse loop module is independent of the track format.
  • Our KSM is undetectable by feedback, which means your feedback will not show "Occupied" just because the reverse loop module is connected to it.
  • Only the locomotive triggers an occupancy message as usual. 
  • The KSM is fully RailCom-capable. The RailCom data channels 1 and 2 of the locomotive are themselves
    sent back via the KSM section.
  • It can be switched between automatic and manual mode, for this you must have a normal switch output on your decoder or LoDi operator.
  • Our modules support the LoDi-KSM(-P).
  • LoDi operator 16-SD-FL
  • But it can also be controlled with any other switching decoder. 


1. The LoDi-KSM(-P) and its connections



  • (1): The track cable coming from the booster or digital control center is connected here. 
  • (2): The terminal loop or the track section that is in the terminal loop is connected here.
  • (3): Used for manual operation via a switch decoder.


2. Overview of connection details


Here you can see the connection variant on a LoDi booster.

All common digital command stations and boosters from any manufacturer can be connected to the LoDi-KSM(-P). The module works completely independently.


This connection example uses the LoDi-KSM(-P) via an occupancy detector.

This is required if you want to report back your reverse loops or report them occupied.

Occupancy detection modules from any manufacturer can be connected to the LoDi-KSM(-P). 



3. Connection to LoDi operator or points decoder


As already mentioned, it has 

LoDi-KSM(-P) a connection for a turnout decoder of any kind. 


On the next photo you can see an example of a connection to a  LoDi operator 4-WD-DC  .


If you now want to switch off the automatic function of the module, the two dip switches at (1) must be set to "off". After that, the module can only be controlled via the points terminals (Decoder IN).


The module has 2 operating modes that can be set:

  • Dip switch ON / ON
    module works in auto mode,
    ie it switches over when a consumer is detected.
    In addition, manual operation is also available in auto mode, which means it is doubly secured.
  • Dip switch OFF / OFF
    The LoDi-KSM only works via the decoder IN terminal.

The LoDi-KSM(-P) modules from 6/2021 have a 3-way dip switch. Here the LED can be switched on and off via Dip 1. Dip 2 and 3 behave as described above. 



4. Specifications


Length 8.9cm

Width 10cm

Height 3.5cm



83 grams 


The decoder can be supplied with up to 26 volts at the digital terminal, i.e. in digital operation.

Pay attention to the information provided by the manufacturer of your digital command station or booster!


LoDi-KSM loadable by consumers with 3 amps for a short time and 2 amps for a long time 


LoDi-KSM(-P) can be loaded by consumers with 6 amps for a short time and 4 amps for a long time