Also it says iDRAC 6 Express next to it, I reccomend googling that if you want more information.It's a Dell thing, not sure on the finer details. It's used for remote management solutions such as crashed memory recovery.
http://www.ebay.com/itm/Dell-iDRAC6...dge-R510-R515-Y383M-JPMJ3-iDRAC-/300871529246
Looks like one of those plugs in to it. It's a proprietary remote access device, so you don't have to dig into the rack and use a KVM. TBH, I wasn't aware that they actually had them as add-on cards, until just now, and figured it was all baked into their mobos.