SmartDecoder 5.1 mfx/DCC/MM/SX 8-pin plug NEM 652. This PIKO SmartDecoder XP 5.1 8-pin plug NEM 652 is a compact, very powerful multi-protocol decoder of the latest generation. It complies with current RCN standards in all areas and can be used in DCC, mfx and Motorola digital systems.