On my Dell PowerEdge R320 I was able to connect this in reverse, which definitely doesn't work. I think it was just my server board, it probably didn't have a newer connector that ensured you couldn't connect it backwards. However, if I align it correctly, it works fine. Please note that when I used it, my server was 1U, so the connector interferes with closing the case. It's decently long and sticks out, but since there's no room in the case for four more drives, I only used it temporarily.