I'm looking at a [MegaRAID SAS 9240-4i Sgl card](http://store.lsi.com/store.cfm/MegaRAID_Controllers/6Gb_SAS_9240_RAID_Controllers/LSI00199) which has a single X4 Mini-SAS SFF8087 connector. As far as I know, such a connector can be expanded to 4 SATA disks. So, I would know how to connect 4 SATA disks. However, the documentation says it supports up to 16 disks in a RAID volume. My question is then; how do I physically connect these 16 disks to the card which only has a single connector?

Is this where backplanes come in (I've tried to find information on that, but can't really figure out how they work together with the RAID controller). ?