KB866: DZ121 - Compatibility with Easy DCC, MRC or Lenz

This article was last updated on April 13, 2017, 12:23 p.m. | Print Article | Leave Feedback

The DZ121 was discontinued in 2002.  There were some interoperability issues with Easy DCC, MRC and Lenz.  The exchange offer is no long valid.  This article is still published for reference only.

At that time, Easy DCC, Lenz and MRC users could return DZ121's to Digitrax for no charge replacements that will work on their systems. There was no reason for Digitrax, Wangrow or NCE users to replace any DZ121 decoder unless they wre having problems.

The text at that time:

For Easy DCC and Lenz users who are having problems: To determine whether your DZ121 should be returned, read back CV07. A value of EF (hex) or 239 (decimal) is current production and will work with your command stations. Other values indicate older code which was the problem and should be returned for no charge replacement.

It was later determined that there were issues:

It seems like no matter how much testing you do and no matter how careful you are, sometimes things can slip through! We built the DZ121 with the full expectation that it would be interoperable with all DCC compatible systems. We did extensive bit timing tests with our lab equipment and additionally with the DB150 and with Wangrow and NCE command stations and did not find problems with the decoder. All of the command stations we used for testing are NMRA "Conforming" command stations so we never expected to see problems with other conforming command stations like Easy DCC, Lenz and MRC.

First of all, we apologize for any problems this oversight has caused for our customers and competitors. Second, to all of our N-scale customers, we say don't worry! We have heard your message loud and clear and we will continue to sell the DZ121 with a disclaimer. This will allow "Digitrax-Wangrow-NCE only" users to enjoy the benefits of a tiny decoder while we look for a work around for users of other DCC systems.

The good news is that the DZ121 does work with Digitrax, Wangrow and NCE based systems. They do not work with Easy DCC, MRC or Lenz systems. This is NOT a problem with ANY command station but is a problem with the DZ121. If you use any of these systems at any time, either as your primary DCC system or at a layout that you visit regularly with your locos, this is bad news for your DZ121 equipped locos. If you use your DZ121 equipped locos only on Digitrax or Wangrow or NCE layouts then you won't have any problems with the DZ121.

This problem does not affect any other Digitrax decoders or decoders made by other DCC manufacturers.

If you have already purchased DZ121s and find that they will not work in your situation, please return them to you Digitrax dealer for exchange.

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