The circuit board has been developed for Märklin locomotives of the BR 05 series, such as item 37050, and fits exactly in place of the original decoder.
For decoders with a 21MTC interface.

This adapter is also suitable for sound decoders. Locomotives with Hall sensors are supported with a compatible decoder (such as ESU LokSound).
The Aux1 to Aux4 connections are routed directly from the 21MTC interface to pads. The function of these connections depends on the decoder used.

Manual 8049