Marklin mSD SoundDecoder. Gauge: H0. This decoder is for converting 36xxx series Marklin/Trix H0 Hobby locomotives. The marklin mSD SoundDecoder has a 21-pin connector and an accompanying connector circuit board for converting 36xxx series locomotives with trucks. The marklin mSD SoundDecoder supports the digital formats mfx, MM 1, MM2, and DCC. The decoder has preset sound for an electric locomotive (TRAXX).