This is an adapter circuit board to allow the new 55029 large railroad decoder to be plugged into the Märklin 60971 decoder programmer. This makes an easier connection to a PC / Laptop. The Märklin Decoder Tool Software is still required and it can be downloaded easily from our homepage (www.maerklin.de unter Service/Downloads/Nachrüstdecoder/mLD3/mSD3). This will allow you to download existing or self-recorded sounds easily. Other settings such as maximum speed, braking behavior, etc. can be programmed quickly and simply with it.