I always forget about the SLC5/04 (mental block I think). That's very different. You could put a 1784-U2DHP adapter in the panel, have it plugged into a USB hub and access the hub through a pass-thru connection but depending on where you get the DH+ to USB adapter you'd be spending a few thousand dollars. You could replace the SLC5/04 with a SLC5/05 but same issue (cost). I'd open the panel. I don't believe you'll find a pass-thru with the correct connection type but it is certainly worth looking for. Having said that, regardless of what it takes to connect to it, I'd migrate away from the SLC5/04 anyway but that's just me (there is a reason for the mental block).