The feedback decoder can be used with the Märklin Interface, the Märklin Memory, the Uhlenbrock Intellibox and the Viessmann Commander. The 16 inputs of the module can be connected to switching tracks, Art. 6840 (H0) switching contacts or, with Märklin K and C tracks, directly to contact track sections for busy signals or for triggering memory switching functions. A 15 cm long flat cable with original s88 connector is included.