ZIMO MS440D Standard DCC Sound Decoder - NMRA-NEM660 21MTC Integral Connector

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  • ZIMO MS440D Standard DCC Sound Decoder - NMRA-NEM660 21MTC Integral Connector
  • ZIMO MS440D Standard DCC Sound Decoder - NMRA-NEM660 21MTC Integral Connector
  • ZIMO MS440D Standard DCC Sound Decoder - NMRA-NEM660 21MTC Integral Connector
  • ZIMO MS440D Standard DCC Sound Decoder - NMRA-NEM660 21MTC Integral Connector
  • ZIMO MS440D Standard DCC Sound Decoder - NMRA-NEM660 21MTC Integral Connector
MSRP: AUD $179.41
Price: AUD $143.75
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ZIMO Elektronik... World Class Motor Control... Exceptional Value...

ZIMO DCC decoder ship to us blank (or mute, or no pre-loaded sound file, or...) unlike other decoder options that we offer.  ZIMO has worked hard to develop a thorough, high quality sound file catalog covering many prototype models from many regions around the world.  ZIMO is a small company with limited resources and is simply not able to produce every possible sound through their own effort.  A network of so-called Sound File Authors has emerged as a result which has helps to grow and expand the ZIMO Sound Database.  This group of Sound File Authors are partners of ZIMO, not employees.  Each has their own specialty and area of expertise and work closely with ZIMO to ensure the files meet the high quality standards ZIMO users and fans have come to expect.

There are three type of Sound Files available in the ZIMO Sound Database, which can be quickly identified by their respective color code:

  • Free (Green) - Files available for download directly from ZIMO for general use for no additional charge.
  • Coded (Blue) - Third-party files created by Sound File Authors which require the purchase of a Load Code for use.  
    • Each Sound File Authors is assigned a unique number or Author Code that acts like a "lock" on the sound files they have developed.  Each ZIMO sound decoder has a unique serial number assigned when it is manufactured and it is stored in CV250, 251, 252, and 253.  A Load Code is a numeric key assigned to a specific decoder serial number and written into CV260, 261, 262, 263 that unlocks that decoder for use with sound files created by the Sound File Author for which the code was generated.
    • Coded files are limited to the decoder and author for which the Load Code was purchased.  Once a Load Code is purchased and the values written into the decoder (CV260, 261, 262, 263), you are free to load and reload any file offered by the author on the decoder for which the Load Code was purchased, i.e. the Load Code is specific to the author and decoder for which it was purchased, not the sound file.
    • Once the Load Code is written to the decoder, the process to load sound files and edit CV values is the same as any other ZIMO decoder.
  •  Pre-Loaded (Red) - Exclusive files developed by an author for their own distribution and use.  These projects are listed in the ZIMO Sound Database but are not available for download.  Contact the author directly for details and availability.

ZIMO offers the ZIMO MXULFA Decoder Update Module with LCD Display and ZIMO MSTAPK2 DCC Decoder Test and Connector Board - Small Scale with E24 Interface and the ZIMO MSTAPG DCC Decoder Test and Connector Board - Large Scale which can be used to load sound files, update decoder firmware, program CV values, test and troubleshoot decoders or installations, and even to create your own custom sound files.  Please note, you must use the ZIMO MXULFA Decoder Update Module with LCD Display to load sound files or update firmware on the MS Series Sound Decoders and MN Series Motor Decoders decoders.  You can program CV's on any ZIMO decoder in Service or P.O.M. mode using your ZIMO MX10 Command Stations & Boosters, any NMRA-compliant programming device or software such as JMRI/Decoder Pro.

SBS4DCC will preload any Free or Coded sound file from the ZIMO Sound Database with the initial purchase of a MS Series Sound Decoders for no additional charge upon request.  Please note, there are numerous third party sound file authors but most of these are offered with a surcharge for use.  SBS4DCC will pre-load third party OEM and non-OEM files in most circumstances but a processing fee may apply.  Please CONTACT US to discuss your specific project or needs.

Regarding firmware updates, SBS4DCC will update the firmware automatically when loading a requested sound file for no additional cost.  There is a modest fee for updating firmware on non-sound decoders.

There are two ways to request that SBS4DCC pre-load a sound file when you purchase a ZIMO decoder from us. The preferred way is to enter the Sound File Number (having the format ZSP00065 or ZSP01064, etc.) in the space above labeled "REQUEST A PRELOADED SOUND FILE (NUMBER OR NAME)".  You can enter a prototype model or prime mover type if you are unsure but using the number guarantees you will get the exact file you want.

The second way is enter the same information noted above in the comments field at checkout but those notes will print on the shipping label so best to use the space provided.

As always, CONTACT US with questions.

ZIMO MS440 DCC Decoders offer the following features:

The MS440 is the "standard 21MTC model" for H0 scale sound in the ZIMO decoder range.  It comes in two variations of a single format, has plenty of power, 10 normal function outputs, 2 convertible logic level outputs, plus connections for external energy storage which is especially important for uninterrupted sound.


  • The predecessor in the "MX world" is / was: MX644.
  • MS440 is only available with the 21MTC interface, but in two versions (-D and -C), which differ in the design of the higher function outputs (FA3 to FA6 as open collector or logic level), although the versions are made using CV- Programming can be converted into one another (for self-correction of incorrect orders). 21MTC was the most widespread interface for a while (around the years 2000 to 2010), but has lost over time compared to PluX, as it actually offers fewer function outputs and there is a certain "standard chaos"; This is related to the fact that it was originally designed for electronically commutated motors ("C-Sinus").
  • There are NO wired versions of the MS440; these would be superfluous as they would have the same properties, dimensions, etc. as the MS450, but with fewer outputs.
  • "MS-Sound" with 3 W fully digital sound amplifier for 8 Ohm or 4 Ohm (or two 8 Ohm parallel) loudspeakers; completely the same as MS450.
  • "Stay-alive": Direct connection for external energy storage - 16 V electrolytic capacitors or 15 V supercap (without upper capacity limit); technically completely the same as MS450, but energy storage connection on wires (due to the interface standard).

Decoder Formats:

MS440C - NEM660 21MTC Integral Connector for locos with built-in MTC interface - convertible to NMRA 21MTC
MS440D - NMRA 21MTC Integral Connector for locos with built-in MTC interface - convertible to NEM660 21MTC

Dimensions: 1.18 x .59 x .16 inch (30 x 15 x 4 mm)


  • 1.2A Continuous-2.5A Peak Power
  • [C] - 4 - Normal Function Outputs
  • [C] - 6 - 5.0V Logic Level Outputs
  • [D] - 8 - Normal Function Outputs
  • [D] - 2 - 5.0V Logic Level Outputs
  • 0.8A Total current with overload protection
  • 2 - 5.0V Low Voltage Outputs
  • 0.2A Total current - Convertible to SUSI
  • SUSI Compatible
  • 2 - Switch Input
  • Direct capacitor energy storage support
  • 3 Watts Audio Power
  • 4-8 Ohms Speaker Impedance
  • 128 Mbit Sound Storage

Feature Summary:

  • 14, 28, 128 speed steps
  • 3-way adjustable back-EMF
  • Selectable frequency for noiseless operation
  • For all DC motors including coreless
  • 3-point or 28-step speed table
  • 5 digit addressing
  • All US lighting effects with programmable timing and dimming
  • Free mapping, NMRA mapping or Swiss mapping function control
  • NMRA bidirectional communication (RailCom)
  • Short circuit protection
  • Thermal protection
  • Reliable overload protection
  • User updateable firmware
  • Editable and updatable sound files

MS sound decoder MS440 to MS990 General and Special Properties

All ZIMO MS locomotive decoders are functionally largely identical.

  • REAL 16 bit resolution
  • 22 or 44 kHz sample rate
  • 16 channels
  • 128 Mbit memory
  • Multiprotocol: DCC, mfx *, MM

The MS sound decoders contain several components that are crucial for performance, but above all the "state-of-the-art" 32 bit ARM microcontroller with DSP properties and a fully digital sound amplifier , the HiFi sound quality with real 16 bit resolution and up to 44 kHz. These decoders are also a flowing further development of the previous generation, namely the MX-Sound-Decoder; almost every MS type has a counterpart with a similar designation in the "MX world". The proven "power electronics" (rectifier, output stages) were largely taken over from this MX world, and of course the designs and interfaces.

With the introduction of the MS generation, there will be ZIMO sound decoders from 2019 which, in addition to DCC and MM, also work with the mfx * rail signal , including automatic registration at Märklin digital centers. Like all ZIMO decoders, they are also capable of analog operation with DC and AC.

Note: Currently (November 2020) there are only MS-SOUND decoders!

The types of the MX range are still available as non-sound decoders . Of course there will also be a change in this area, mainly because it is necessary for mfx control; however, the differences between MX and MS with DCC control will be less significant than with decoders with sound.


  • DCC addresses 1 ... 10239, network addresses 1 ... 9999 (from 2017), MM addresses 1 ... 80, functions F0 ... F28), mfx
  • 14, 28 or 128 (external) speed steps, 256 or 1024 internal steps
  • Programming the CVs in "Service Mode" (on the programming track) and in "Operational Mode" (with RailCom for acknowledging and reading out), under mfx, if available,
  • Undisturbed driving operation (without decoder reset and restart) in the event of contact interruptions up to 1 or 2 seconds (effective even without external energy storage)
  • Automatic continued travel if the wheel / rail contact is interrupted until the supply is restored (if there is sufficient energy storage - "Stay alive" - in the locomotive; see section "ENERGY STORAGE, below").
  • DC and AC analog operation, the latter including a reversal of direction due to Märklin-typical overvoltage impulse (up to 35 V)
  • Update-capable software: new software versions are loaded without opening the locomotive, with the help of the ZIMO decoder update device MXULF (A) or the central controller MX31ZL from the USB stick or directly from the computer via ZSP ("ZIMO Sound Programmer") and MXULF or (planned) via MX10.


  • Overcurrent protection for all outputs, overtemperature protection, for details see info under "Total current"
  • Protection against overvoltage peaks in the motor inductance by suppressor diodes
  • Dielectric strength: at least 35 V (depending on the type).


  • Low-noise high-frequency motor control, optionally with 20 or 40 kHz
  • Suitable for all DC motors and bell armature motors (Faulhaber, Maxxon), with additional diodes also AC motors
  • Also for "difficult cases" like Fleischmann round motors or old motors that are only suitable for low frequencies
  • ZIMO motor control with self-optimization and numerous setting options for manual optimization (PID parameters)
  • Speed characteristic optionally three-point or freely programmable in 28 steps (according to the standard)
  • Alternative "OST-WEST" direction control and feedback, together with base unit MX10 and remote MX32
  • (from SW version 5.00) km / h control (per speed step 1/2 km / h, 1 km / h or 2 km / h) as an alternative to conventional speed step control,
  • (from SW version 5.00) adjustable measure to compensate the gearbox backlash when reversing the direction to avoid the starting jolt
  • (from SW version 5.00) ZIMO acceleration settings ("conforming to the standard", additionally "exponential" for smooth starting / stopping, "adaptive" against starting jolt)
  • (from SW version 5.00) maneuvering key functions (half speed, reduction or switch-off of the start-up / braking time, optionally with F3, F4, or MAN)


  • Full NMRA function mapping for F0 - F12, as well as ZIMO extensions (direction-dependent assignments, etc.)
  • Dimming, blinking, American (Mars, Ditch, Strobe, ...) and other light effects (soft start, brake light, flickering, automatic time-out, ..)
  • High beam / low beam switching via function key, one-sided light suppression, configuration of smoke generators, etc.
  • "ZIMO Swiss Mapping" for complex lighting conditions depending on several function keys, with individually assignable dimming and flashing functions
  • "ZIMO input mapping", especially for the user to exchange the function keys without changing the actual configuration
  • Time-limited clutch control for Krois and Roco clutches; "Clutch waltz" (automatic pressure to relieve the hook and move away)
  • SUSI interface on the connector or as soldering pads, for large scale decoders with a 4-pin "SUSI plug"
  • In addition to the actual function outputs, all MS decoders have "logic level outputs", for example as servo control lines or with an external transistor for normal consumers (LEDs, etc.)
  • All decoders with servo control: designs for N to H0 as a secondary function of the SUSI connections, large scale decoders with full 3-pin servo connections including 5V supply. Servo configuration with special CVs for end and middle positions, rotational speed, function assignment.


  • DC braking sections, ABC (stopping via asymmetrical DCC signal), "Märklin braking section"
  • ZIMO "signal-dependent train control" (HLU) with speed limits in 7 levels, from "full speed" to "stop": F, FL, L (slow), LU, U (slow), UH, H.
  • ZIMO train number recognition in connection with ZIMO digital system and ZIMO track section modules MX9
  • (in newer applications, especially with StEin modules or Roco feedbacks, the feedback works via RailCom)
  • (from SW version 5.00) constant braking distance in two course variants (braking always begins immediately, or the later, the lower the current speed is)
  • RailCom: km / h feedback, CV "on-the-main" readout and confirmed programming, east-west feedback, quality-of-service, track search, RailCom address feedback, and many other RailCom applications are planned for future software versions.


  • Loading the sound projects similarly (with the same equipment) as loading the new software version (software update, see above), i.e. with the help of the ZIMO decoder update device MXULF (A) or the central controller MX31ZL from the USB stick or directly from the computer via ZSP ("ZIMO Sound Programmer") (planned) via MX10.
  • Alternative fast charging (3 to 5 min instead of 30 to 1000 min) via SUSI interface (i.e. SUSI pins with proprietary protocol)
  • Powerful sound amplifiers: in miniature sound decoders 1 watt for 8 ohm loudspeakers; in H0 sound decoders 3 watts for 4 or 8 ohm loudspeakers (also two in parallel); in large scale sound decoders MS990 10 watts for 4 ohms or 8 ohms loudspeakers (also two in parallel) on a 10 V basis,
  • REAL 16-bit resolution encompasses the entire sound path: starting with the sound files stored in the flash memory, through the I²C bus (= Inter-IC sound) for stereo output, to the fully digital Class D amplifier . ZIMO dispenses with the cheaper digital-to-analog conversion (with 10 or 14 bit) and amplifiers with analog input (also called Class "D"), which are otherwise frequently used.
  • Playback rate 22 kHz (standard); but also channels (defined by the sound project) with 11 kHz (only at 8 bit) for simple noises, such as announcements, and 44 kHz for maximum possible hi-fi sound quality.
  • The MS decoders have a sound memory of 128 Mbit, which enables a playback time of 360 seconds (with 16-bit sound with 22 kHz). With 8 bit sound at 11 kHz, up to 1440 seconds are available (neglecting the overhead).
  • New sound projects have a resolution of 16 bit; but also previous sound projects with 8 bit sound audibly better with the MS decoders, which is due to the use of a technology for interpolation, which is available in ZIMO decoders thanks to the high computing power of the microcontroller.
  • Up to 16 sound channels are reproduced at the same time (e.g. chuffs, air pump, whistle, ...) and can be distributed to two loudspeakers with "stereo decoders" (especially for large railways, but also planned for H0).
  • Synchronization of the chuffs either by connecting an axis detector (mechanical, LED, Hall) or by a simulated axis detector, both for the sound and for the smoke fan controlSound collection as a special form of the sound project: it contains sound samples and parameters for several series. For example the europ. Steam / Diesel Collection with 5 sets of steam chimes, 10 whistles, 2 bells, ... Free selection from the available samples using a real-time procedure to create individual sounds.
  • (from SW version 5.00) acceleration and load dependency; automatic measurement run to adjust the load dependence


  • Standard HO sound decoder: connection option for external energy storage devices (electrolytic capacitors, tantals, gold caps with unlimited capacity and 15 V or 16 V dielectric strength, even if the rail voltage is higher, e.g. ZIMO SUPERCAP68 or GOLMRUND, GOLMLANG); thus continuing to drive at full power despite the interruption of contact, avoidance of light flickering and sound disturbances, compensation of the energy loss due to RailCom and HLU gaps.
  • Next-sound decoder: the internal tantalum energy storage on a 5V basis can be expanded with external tantalum or gold caps (with proctically unlimited capacity 5 V or 2 x 2.7 V, e.g. ZIMO MINIGOLD); thereby slow driving, reduction of light flickering and sound disturbances.
  • Large-scale sound decoder: the internal 8V-based Goldcap memory (3 Goldcap cells with 3 or 1 F each) in connection with a step-up transformation of the voltage is usually completely sufficient to continue driving despite the interruption of contact, avoiding light flickering and Sound interference. In addition, external energy storage devices (electrolytic capacitors, tantals, gold caps with unlimited capacity and 15 V or 16 V dielectric strength, even if the rail voltage is higher; e.g. ZIMO GOLMRUND, GOLMLANG) can be connected.
  • The following applies to all decoders: with some additional components (diodes, resistors), energy storage devices (mostly electrolytic capacitors, at the level of the driving voltage, preferably 25 V) can be connected to all decoders, even those without special precautions. The efficiency (energy yield) is lower than in the cases mentioned above.


  • Synchronous rectifier instead of diode rectifier for sustainable reduction of the voltage drop and heat loss, therefore continuous current up to 6 A without heat sink.
  • One, two or three function low voltages (up to 1 A) depending on the type of decoder: 5 V (as servo supply, often also for the smoke fan and for lights), 10 V and adjustable low voltage from 1.2 V to just under driving voltage.
  • Up to 14 "normal" function outputs (each 1 A loadable in groups of 4) depending on the type of decoder, plus a special output for the smoke fan.
  • 6 complete servo connections; for 3-pin standard servo plug (5V supply, control line, ground)
  • Gyroscopic acceleration sensor to influence the sound on inclines, curves, etc.

* Note: The decoders of the MS490 series are NOT mfx-capable in order to allow their small size.

"RailCom" is a trademark of Lenz GmbH


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Additional Resources

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Additional Information

Standard (HO-S-O*)
Motor + Sound + Function
NMRA - Marklin 21MTC
NEM660 - 21MTC
SIZE-INCH (L x W x H):
1.18 x 0.59 x 0.16 in
30 x 15 x 4 mm
0.8A total
Hardwire - Solder Pad
On interface connector
44.1 kHz
128 Mbit
4-8 Ohms
Service Mode + P.O.M.
Yes - MXULFA required
Yes - MXULFA required
NMRA DCC, M4, Motorola
NOTES (1):
* - Optional configuration - see manual
NOTES (2):
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