I have Cakewalk7.0 Professional. I have the files (.mid extension) that I am to play into my RD600.

The instructions say to power on my RD600 while holding down PartSelectTX (lower&upper) buttons and I am to have a message on the display that says MIDI waiting. It doesn't happen. What am I to do with the RD600?

How do I play these files into the RD600 with Cakewalk?