LokSound V4.0 M4 - The Compatible

We would like to introduce our newest LokSound decoder. At first glance, it appears to be a normal representative of its kind. However, the decoder´s unique inner values make it a first choice for model railway fans looking for maximum compatibility with all common digital systems.

The LokSound V4.0 M4 is the world´s first Quad-protocol decoder! Aside from DCC, Motorola® and Selectrix®, all incorporated into the LokSound V4.0, the LokSound V4.0 M4 also speaks the M4 protocol! Thus the decoder is a 100% compatible to all mfx®-capable command stations on the market. It will be automatically recognised and can be fully programmed.. That´s why the decoder is “first choice” for all Märklin fans who do not want to miss out on mfx®.

To ensure that almost all locomotives can be retrofit with this multi-talented decoder, we offer the LokSound V4.0 M4 with many different interfaces such as 8-pin, 6-pin or PluX12 plug as well as wireless 21MTC or with a PluX16 interface as well as versions with PluX22 Interface for the latest Fleischmann® or ROCO® vehicles.

Operational modes

The LokSound V4.0 M4 is a real multi-talent. It speaks 4 data protocols and can thus be really used anywhere. Except during DCC operation with RailComPlus® recognition, the decoder will be automatically recognised by Märklin® command stations via the M4 protocol. For owners of older layouts, the decoder has additionally been equipped with the well-known Motorola® and Selectrix® data format.

The LokSound V4.0 M4 can be also used on analogue DC or AC layouts. The built-in motor control will learn the motor manners and synchronise the drive and lighting functions with the sound functions. So, model railroaders without a digital system can also enjoy the LokSound decoders, of course, despite the sounds triggered by function keys. No matter with which command station you operate the decoder it will always be perfectly integrated. Thanks to its M4 recognition, it will be automatically detected by Märklin Central Stations® and 16 functions will be available. Of course you´ll be able to adjust all parameters with your command stations as you are used to do.

During DCC operation there will be up to 28 functions available. The decoder will be automatically recognised in a matter of seconds by an ESU ECoS with RailComPlus® detection and show all functions as well.

Owners of the “older” Märklin® 6021 will be not excluded for sure. 4 addresses per decoder enable to switch up to 16 functions. A built-in programming mode makes reprogramming ,even with this dignified command station, possible. Last but not least it should be remembered that the decoder can be operated reliably with Selectrix® command stations.

All of this sounds far too good to be true? It gets even better: The LokSound V4.0 M4 decoder recognises all common break systems, such as the Märklin® break system, the Lenz® ABC break system (with slow drive function!), Selectrix® diode break systems or ZIMO® HLU® systems: the decoder will always recognise the desired operational mode full-automatically. For us being the creator of this function, it is a matter of honour that during braking a constant distance can be defined.

Motor control

You expect an excellent motor control from a LokSound Decoder and deservedly so! LokSound V4.0 M4 is equipped with the 5th generation of load control. You can adjust the control frequency adaptively to the speed. So many motors will run even better and softer. You can determine a limitation of the load control‘s influence with the Dynamic Drive Control (DDC) to control very accurately in station or shunting switch areas. Uphill running also appears very natural with it.


The most important element of the new LokSound V4.0 decoders is the sound chip. This is why we have equipped the LokSound V4.0 M4 with an enormous memory of 32 MBit to save up to 276 seconds of original sounds. The LokSound V4.0 M4 works with 8 polyphonic channels, i.e. that the decoder is able to play up to 8 different sounds simultaneously, using the 16-Bit mixer and the nearly noiseless D/A convertor.

So we can provide a much better monitoring of the original locomotive´s complex elements as it is possible to combine several channels. You‘ll recognise the difference at once! The sounds will be transmitted to the loudspeaker using a new digital „class D“ amplifier. Combined with the ESU high performance speakers (with an impedance of 4-8 Ohms) you will achieve an unprecedented sound quality! Each individual sound can be mixed in volume independently via CVs.


LokSound V4.0 M4 decoders have six (6) function outputs, each with a constant current of 250mA. The versions with 21MTC interface have two more non-amplified outputs with logic level to meet the NEM 660 standards. All important light functions like Flash, Gyrolight, Mars light, fire box and so on are provided including the individual adjustment of brightness for each function. Of course, the decoders provide automatic coupling and decoupling for couplers by Roco®, Krois® and Telex® and from now on even a full beaming head light function. The LED mode controls the right light effects when using LEDs. These features will, of course, also work with mfx® command stations (e.g. Märklin® Central Station 2).

Safe operation

If desired, it is possible to connect a PowerPack (ESU 54670, see page 62) to the LokSound V4.0 M4, as to all other ESU V4.0 decoders. This energy storage continues to supply the decoder with energy if the power consumption is not optimal due to dirty tracks.


Of course, all function outputs and the motor current output are overload protected. We want you to have fun with your decoder as long as possible!

Future built-in

You can update the firmware of the LokSound decoders. This means, the internal software on the decoder‘s memory can be replaced by new versions if necessary. You‘ll simply need the ESU LokProgrammer and a PC.

Sound variations

ESU, as the technologic and market leader takes your requirements for sound very seriously. For the LokSound V4.0 M4 decoders, all sounds created for the 4th generation of LokSounds can be used - or projects that have been created for a LokSound V3.0 M4 can be converted just by a few mouse clicks. There are already more than 200 sound variations available. ESU is extending the sound library all the time and provides all sounds on our homepage for free download.

Operational modes: NMRA/DCC with 14, 28, 128 drive steps and automatic RailComPlus® detection.
  DCC 2-digit & 4-digit addresses. Up to 28 functions in DCC operation.
  M4 data format with 128 speed steps and automatic recognition by appropriate command stations. Up to 16 functions in M4 operation
  Digital Motorola® (old and new), up to 28 drivesteps in Motorola® mode. Up to 255 addresses in Motorola® mode. Up to 4 addresses for function keys F5 to F15.
  Selectrix® operation with 31 speed steps. Extended functions for up to 8 function keys (suitable control station necessary).
  Analogue DC and AC operation (deactivation possible).
  Automatic recognition of the operating mode and the DCC drive step configuration.
  Supporting Lenz® LG100, Märklin®, Roco® braking modes. Supporting Lenz ABC brakes and Märklin® brake system
  Reverse bit
  Intelligent programming mode with Märklin® 6021®. Supporting programming modes for ROCO Lokmaus 2 and ROCO Multimaus.
Drive control bit: 1.1A continuous load
  Connection to DC-, AC-motors with permanent magnet
  Noiseless, motor saving control with 40 / 20 kHz pwm frequency
  Motor output protected against overload. Load control of the 5th generation (possible to deactivate) Dynamic Drive Control.
Function outputs: 6 amplified outputs on wired versions, 4 amplified outputs + 2 logic outputs on 21MTC interface versions (+2 logic outputs parallel to AUX3 and AUX4 for 21MTC version)
  max. 250mA load for each output
  Total current for all function outputs ca. 500mA. Outputs short circuit protected
Sound unit: 8 (!) individual sound channels
  High power stereo amplification with about 1.8 Watts output current
  Soundfiles in the internal flash memory modifiable
  Modes for Steam-, Dieselhydraulic- , Dieselelectric- , Electric locomotives, battery railcars, hybrid locomotives etc.
  32 MBit sound memory (up to 276 seconds)Connection for two independent loudspeakers
Energy buffering: Connecting for ESU 54670 PowerPack available
Communication: Full RailComPlus® integration. Full M4 integration. Susi interface.
Loudspeakers: Impedance 4-8 Ohms, 4 Ohms recommended. Special speaker 4 Ohms, 23 mm diameter (4 Ohms) included in delivery
Dimensions: 30.3mm x 15.5mm x 5.5mm (1.18 x 0.61 x 0.22 inch)
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