This decoder is for converting Märklin/Trix H0 36000 series Hobby locomotives. The märklin SoundDecoder3 has a 21-pin interface connector and an accompanying interface connector circuit board for converting 36000 series locomotives with trucks.The märklin SoundDecoder3 supports the digital formats mfx, MM1, MM2, and DCC. The decoder has preset sound for a diesel locomotive (Herkules).