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Dispatch: My wife is currently pregnant and in the government-defined more vulnerable group, so I have had to suspend next day dispatch and reduce the amount of contact that we have with public spaces. Until national restrictions are relaxed, I will ship orders at mid-day each Tuesday. Where possible, I will try to post items that are not 'signed for' on Fridays as well, but I cannot guarantee it. Please rest assured that orders will be shipped as soon as they can be, but it may take a few days longer than normal.

Thank you for your understanding and support. Stay well.

21-Pin DCC Breakout Board (MTC21 Socket and Solder Tabs)


In stock


A brand new 21-pin NEM21 adaptor (with solder pads) for 21-pin chassis. It is designed and manufactured by Strathpeffer Junction.

This breakout board allows you to use an 8-pin, 6-pin or wires-only decoder with a DCC ready 21-pin MTC locomotive or multiple unit.

The board is compact, making it suitable for the majority of models. It is the ideal solution for the many situations where an 8-pin plug and 8-pin to 21-pin adaptor is too bulky to fit.

Special feature: Two pads for speakers are also provided, making it perfect for DCC sound installations.

The adaptor is compatible with all common brands of 8-pin decoder, including ESU (LokPilot and LokSound), Zimo, Gaugemaster, Digitrax, Hornby, Bachmann and LaisDcc.

Dimensions: 17mm x 16mm x 3.5mm (approx.)

Wiring Advice

The breakout board has the colour of each associated wire marked adjacent to the corresponding pad, however due to its small size, we have reproduced the text in the diagram below for ease of reference.

Unlike other similar breakout boards, two pads are provided to enable you to solder the speakers wires from a DCC sound decoder to the adaptor, so the decoder can link through to any speakers solders to the model’s PCB.

In addition to forward/reverse lighting and the normal Aux 3 (green) channel, and breakout pad is also provided for Aux 4 (violet/purple), to accommodate 8-pin decoders that come with a trailing Aux 4 wire.

Note: The colours notes relate to the NMRA/NEM standards, however we cannot guarantee that your decoder will correctly follow them. Please triple check which wire leads where before powering up the model/decoder. Please also check all solder joints for shorts, and insulate where necessary, before applying power.

Wiring diagram

DCC sound use

If used with an 8-pin DCC sound decoder, you have two options:

1) The speaker(s) may be soldered directly to the wires emanating from the decoder, or

2) If you have soldered speakers to pads on the model’s PCB, you can solder the decoder’s speaker wires to the pads provided on the adaptor, and they will link through to the pads on the PCB.

If there is any doubt, please refer to and follow the decoder manufacturer’s instructions or contact us for advice before applying any power.


We can accept no liability or responsibility for any damage or injury occurring from the installation and use of this adaptor. Installation requires modifications to DCC decoders and/or models and the use of tools, some of which have the potential to damage you and/or you models, as well as other components and equipment. Users must not commence work unless they are confident that they have the skills and experience necessary to complete it successfully, and install these adaptors and undertake work to their models at their own risk. Whilst we check all adaptors for obvious flaws prior to shipping, we do not probe every contact or examine every solder joint under a microscope; it is your responsibility to check and test them fully before use and, specifically, to check for shorts or incorrect wiring before applying any power to the layout, model and/or decoder. If you are in any doubt, you must consult the decoder or model manufacturer or contact us for assistance before powering anything up. We are not responsible for, nor liable for any damage caused through the installation or use of this product.

Additional information



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