At work I've received a new ThinkCentre M57 tower computer and looking inside I see that in the SATA cluster 3 of them are orange and the 4th one is black. Any reason for this? Sadly the Hardware Maintenance Manual and User Guide are no assistance.

The black one is eSATA, for external devices, I think about the same standards EXCEPT the cabling is different, can't hook a SATA cable to an eSATA port.

EDIT: I just received a new M58, the black SATA connector is marked as an eSATA connector. Apparently ONLY the external portion of eSATA connectors are required to be a different plug. I intend to install a 2nd internal optical drive and the goal is to interface to the 'black" eSATA port. This should work, a regular SATA cable will physically plug into the designated eSATA port, so I don't see why this wouldn't work.

SHG