A lot of newer devices nowadays have a 3.5mm jack for MIDI-Out. Unfortunately – unlike the regular DIN5 plugs – there is no standard in this type of MIDI-Out. You could say there is a polarity issue. One manufacturer uses polarity A, the other uses B.
Whatever TRS MIDI Output you may have on your device; With the RK-TRS-X (and a standard minijack-audio cable) you can convert any TRS-MIDI to DIN5 MIDI by putting one of these onto the audio cable.