The circuit board has been developed for the Märklin locomotives of the Am 842 series and fits exactly in place of the original decoder. All decoders with 21MTC interface are suitable, preferably with amplified outputs Aux3 and 4.
The connections Aux3 and Aux4 are led out from the 21MTC interface on pads, whereby Aux3 is led via a 3.3kΩ resistor, so that an LED can be connected directly, e.g. for a driver's cab lighting.
A decoder with amplified outputs Aux3/4 is needed for this.

Size of the PCB (L x W): 132 x 15.5mm

By means of function mapping in the decoder the following light signals are possible (Example):
- F0 (light) A-light in front, direction-dependent
- F0 and F1 A-light in front, one white lamp in the back, bottom right. Directional.
- Only F2 shunting light: one white lamp at the bottom right on both sides.
- F5 Cabin lighting

Operating manual 8070L