MTH HO DCC Compatiability and DCS

Discussion in 'DCC & Electronics' started by RailStop, Oct 26, 2008.

  1. RailStop

    RailStop New Member

    The link below points to a document that explains the level of DCC compatibility found in MTH, HO locomotives. It also gives an overview of their DCS (Digital Command and Control System). It is hoped this information will be useful for people considering the purchase of MTH locomotives. We all know they have recently announced the SD70ACe in HO.

    The document is too large to upload so you will have to click on it or paste the link into your browser.

    Extremely brief summary of MTH DCC as shipped to-date. Much more detail in the document.

    MTH DCC Overview

    The MTH locomotives are designed primarily for MTH DCS but support DCC compatibility. Although the MTH locomotives operate well in DCC, only a few CVs are available for configuration. In place of CVs, MTH uses function keys to control DCC functions and parameters. This approach limits DCC capabilities. These limitations are addressed in the text that follows.

    MTH Supported Standard CVs

    CV 1 Short Address
    CV 3 Acceleration Rate
    CV 4 Deceleration Rate
    CV 17-18 Extended Address (upper bits must be set to 1)
    CV29 Bits 5 = ext. address; bit 1 = Direction bit (only features supported in CV 29)

    MTH Extended CVs

    49 Short Address (controllers that prohibit address POM)
    50 & 51 MTH only CV - Extended Address (controllers that prohibit address POM)
    55 Reset Send value = 55 to CV 55 to reset the decoder.

    MTH DCC Compatibility Issues

    The following significant DCC features are not supported in MTH locomotives.

    • Advance Consisting – Consisting must be done using the DCC system’s consist capability which does not support enabling or disabling function keys on a per locomotive basis. Also the consist is not portable.

    • CV min, mid, and max for sitting a three point speed curve and matching locomotive speeds for consisting. It is not possible to speed match your MTH locomotive to a DCC locomotive. You may be able to match your DCC locomotive to your MTH locomotive.

    • Speed Tables – No custom speed tables.
    • Individual sound volumes – master sound can be set to three levels with F7
    • Function key remapping
    • Modification of lighting operation
  2. jbaakko

    jbaakko Active Member

    It's the Union Pacific heritage fleet, not BNSF.

    Sounds like I may have to replace the decoder with a Tsunami, if I should decide to buy the MTH SD70ACe. Great article though. One question, not sure if was covered. Could you configure the volume with DCS then program it to run on DCC, with the pre-edited sound volume/options?
  3. RailStop

    RailStop New Member

    Reply to Josh


    Thanks for pointing out the typo. I am so used to BNSF Heritage my reflexes tool over. Pardon you all UP Heritage fleet!.

    Yes setting the volume and other things in DCS configures DCC. I set the whistle and chuff volumes and the settings carried through to DCS. Otherwise my K4 would have been on a long, one-way journey. I have no plans to consist my K4 so this works.


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