Your reply is a good start for beginners, but my problem is specific to Roland instruments. I don't know how to explain it any better than I did, so let me give you a hypothetical example.
I have a student with a Roland piano who likes Disney music and is ready to be inroduced to the key of Bb. So, I go into Band-In-A-Box and create a backing sequence for "Under the Sea" using a suitable Calypso rhythm. I then create a MIDI file out of the BIAB file and open it up in a Cakewalk sequencer. BIAB has automatically assigned its various instruments to various channels: typically, melody is on 4, bass on 2, drums on 10 and piano on 3, etc. I use Cakewalk to tweak the file a little and then save it to disk and bring the disk to the student's house. I want to show the student what the various instruments are doing by turning off some channels but not others. I also want her to "turn off" the melody all week and play it herself. However, her Roland piano does not have buttons for the channels labeled by number; instead, the buttons are labeled "Melody" or "Bass" or "Accompaniment." So, I hit the "Melody" button to turn it off, but instead the bass disappears! Or I hit the "Accompaniment" button and the melody disappears! I figure the problem is that I am assigning the instruments to "incorrect" channels. But I don't know which channel is supposed to be what in the Roland scheme of things! Is the "Melody" button in fact a "Channel 1" button? Drums at channel 10 do seem to work on the "Drums" button, but everything else is messed up. Has anyone out there figured this out?
I guess I have 2 other options: 1) Ask a student if I really can come to their house with a MIDI file that I have well documented and spend an hour or so figuring out what disappears when, and then changing the channel assignments back home and then going BACK to the student's house to double-check it, OR 2) going to Roland's website and asking them. Well, I guess there's a 3rd option; buy a Roland product and figure it out at home!
Thanks for any help you can give.