Marcus Curtis
M_Glenn_M
So the Drum machine also has MIDI in and out but not thru.
Does that mean I can't use the drum machine to midi my Gr20 to Sonar?
yes
Right. Not possible, due to lack of THRU port.
However, you can record MIDI from your GR into your DR (with the DR in "MIDI storage" mode) and then later transfer it via USB into Sonar (with the DR in USB MIDI mode). Might want to try that.
(might have the settings backwards/wrong, going by memory here, but the manual should make it clear, since you can only use the DR's MIDI ports or the DR's USB, not both at the same time, depending upon the mode you set, but I do know it can in fact be done)
You can of course also use your GR as a MIDI controller for the DR as well, say, if you wanted to play some bass sounds. Try it!