Marklin sound decoder MSD3. Conversion from Marklin/Trix H0 locomotives with built-in high-performance motor or other DC motors. The Marklin sound DECODER3 has a 21 pin interface and complimented by an interface plate designed to replace analog and digital locomotives. The Marklin sound DECODER3 supports the digital file formats MFX, mm1, mm2 and dcc. default sound an electric locomotive.