Hi there, I'm new. Please bear with me. I'm a keyboardist and this is my first MIDI controller experience. Please help me learn! I have the following pieces: -MacBook with OS 10.6.7/1.83 GHz Intel/2GB 667 MHz DDR2 SDRAM/Garageband/etc. -Roland PC 200 MK II MIDI Controller -MIDI interface cord: One end is USB and the other side has two ends: IN and OUT. I successfully installed the driver for the interface on my computer. That's about all the success I have had. I would like to start using the controller simply by using it in Garage Band. The back of my Roland controller has a "MIDI OUT" port. Which part of the interface cord do I plug in, "IN" or "OUT?" Thanks for your time, I know this is a very knowledgable forum.