Thanks NCS. Are these LGB/Marklin decoders basically Massoth decoders rebranded? .
So far as I know, the answer to this is probably no.
These are TRIX decoders - which is another Marklin subsidiary. They have the TRIX product code number in CV 8.
I think these are a Marklin 'innovation' to fit in with their central station technology. Someone else here may know for sure where the technology comes from, but I suspect it may be from Marklin's smaller scale models, originally. Whether they have somehow grafted this onto Massoth decoder technology, I cannot say.
There is an article on page 30 of issue #2 2016 of the LGB/Marklin user magazine, that indicates how this 'modern' MFX decoder technology can be retro-fitted into older LGB models using a recently released LGB 55529 interface connector/adapter. There is even a photo of a 28pin decoder, which I assume to be the TRIX [I haven't opened up my loco to look at mine]
There is a link to the overview of the magazine here, but I couldn't find an online copy of its contents.
http://www.lgb.com/en/service/publications/lgb_depesche.html
Allaboutlgb.com has a page [
http://www.allaboutlgb.com/lgb decoder installation.html ] that describes the various interfaces to decoders in LGB locos. It includes the comment "
In 2014 LGB introduced a new 28-pin decoder interface which they represented in their literature by symbol "6". The interface, sometimes referred to as the LGB/Märklin Gauge 1 interface, is plug-and-play compatible with the LGB® 55028 decoder, the Massoth eMOTION XL-M1 decoder, and the Massoth eMOTION XLS-M1 sound decoder."
This interface would appear to be the LGB 55529. A quick search shows this interface on sale in several well known vendors. This Amazon page even has a picture:
https://www.amazon.com/LGB-L55529-55529/dp/B00JQPRZ0I
Putting all this together, I would surmise that the Marklin decoder is a completely new type, which has to be retrofitted to LGB locos. The advent of the 55529 interface in 2014 probably made it practical to add these to LGB locos, without changing the basic LGB architecture. If you have looked at your MFX decoder, you might be able to see whether it is connected via one of these 55529 interfaces. [or maybe this is
only used to convert older LGB locos to MFX?]