Is something missing here?

[Happy Vibe]

When they installed it they should have brought the cable out to the front somewhere. The stereo I installed in my van had the same thing and I ran the cable into the glove box. These units have a trim ring that you pull off then there will be screws that let you pull the unit out.

[Stinkielee]

Update 5/5/2015: We have discovered that an SD card DOES work in the slot after all! But we are still befuddled about the USB port. The manual clearly states: "Connect a USB device to the black USB input connector on the back of the unit." I have no intention of taking anything apart on this brand new, expensive thing, so I have a email for Dual. I sent them photos and explained my dilemma. Hope they respond with something simple and don't make me feel too stupid!

[rana]

Originally Posted by Stinkielee

So how in the heck would someone get to the BACK of the unit? And why? I'm into a bottle of port wine now....LOL

You use a port extension cable. It plugs into the rear then you can place the extended port anywhere you like. They do that because it allows for flexibility to run it where you want.. ie. dash mounted device, plug into a permanently mounted in dash, audio or video in dash install, etc.

As I mentioned earlier.. you MAY already have one installed. It's typical to route the end of the extension cable to the glove box.

[itat]

If you don't already have it, the manual can be downloaded from here:
http://www.dualav.com/support/manuals/xdvd3201.pdf

To get it out, you need to remove the bezel trim (it should just pull off) and use special "keys" on each side to release it from the mounting sleeve. If you're not comfortable do it, any decent car audio place will be able to do it for you in under a minute.

The large black plug on the back of the unit is the USB port where you plug in an extension like Yarome pointed to.

[Stinkielee]

Thank you itat. That surely will be the solution. I will report back on this thread when I get this done. Awesome!