I need some guidance regarding my CLIMAX the box says  it is plug and play ready    ,,  and I just need to plug in a decoder....is there a difference between a sound card  and  a loce control decoder    and  what  would be the best choice for me....I hhave An MRC  Prodigy advanced2   DCC controller  with a power booster for large scale ..   Can someone tell me  if  this spectrum loco  has a decoder already    and   ll I need  is  a sound card      Im so confused