What is the purpose of using the Midi Interface? Maybe you don't NEED this? Or is there more to your setup that you've not mentioned?

Did connecting the Roland (keyboard ?)to the other keyboard (which ?) work, or not? Which will be controlling the other?

The Midi Interface may be intended for a far more complex setup than you have? You could easily find it gives more problems than help.

Geoff

Thank you for your response, I do indeed have other midi equipment to hook up. What I wanted to know is can I use
the Subzero 4i/4o as a junction box and would all my midi devices still communicate with each other as if they were directly connected?

I have a Roland JD-Xi, a Novation X Station, a Novation SL49 MK2 MIDI controller and a Mackie Control Universal(not the pro)
and want them all to be plugged into the Subzero 4i/4o. Ultimately, I want my master keyboard to be the Novation SL49 MK2