This decoder is for converting Märklin/Trix H0 locomotives with built-in high-efficiency motors or other DC motors. The märklin LokDecoder mLD3 has a 21-pin 21mtc (adheres to NEM 660) interface connector and an accompanying interface connector circuit board for upgrading analog and digital locomotives.
The märklin LokDecoder mLD3 supports the digital formats mfx, MM1, MM2, and DCC.