Hi Folks, can you tell me what's the difference betwenn these 3 models of the MX204? MX204 JNP204/MX204 Fixed 1 RU System includes 3 Fan Trays and 2 Power Supplies MX204-IR JNP204/MX204 Fixed 1 RU System -IR MODE includes 3 Fan Trays and 2 Power Supplies ...