Lenovo ThinkStation P500 Configuration Manual page 40

BCA-S : Blind Connect Assembly consisting of four 8482-SFF (U.2) ports (supporting SAS or SATA drives).
The assembly also contains the following cable connections:

One 4-pin power connector that connect to the motherboard

One mini-SAS HD connector that connect to either the onboard controller or Avago
controller labeled "S/X"

LED lights light up next to each port to show which ports on the BCA are available when
either the Avago or Intel onboard controller is used.

The Avago controller supports all the given ports on the BCA.

The onboard Intel controller supports only two of the given ports on the BCA.
Connector Type
8639-SFF (U.2) PCIe port
8482-SFF port
Drives Supported
SATA
SAS (only with Avago controller)
SSD
2.5" PCIe SSDs
SATA
SAS (only with Avago controller)
SSD