There are a few things I don't understand about your description, and I'm not sure I understand exactly what you are *trying* to do. In any case... you have a MIDI cable going from the OUT on your interface to the IN on your DX7, and another cable going from the OUT on the DX7 to the IN on your interface... is that correct? Are you sure you haven't plugged the cable into the THRU port instead of the OUT port? That would explain why the MIDI data is being echoed back to the computer.

If not, I suppose the DX7 is echoing the MIDI data to the OUT port, and there is likely a way to turn this feature off (although I couldn't see it from a quick glance at the manual).

Looking at the MIDI Monitor in Band-in-a-Box is a good way of seeing exactly what's happening.

Note: You can disable MIDI thru in Band-in-a-Box in Opt. | Preferences | MIDI Options. The "Thru" track in Band-in-a-Box is used for MIDI data received by an external MIDI device. e.g. so you could play along in realtime on your keyboard.

Andrew
PG Music Inc.