I got a new raid card for a R410 server since the S300 that came with it doesn't support raid with Linux (No work around for this if SAS from what I could find). The new card is the SAS H200.
Anyways, the RAID card has 2 pins on it and there is a cable that that connects to a 4 pin connection on the riser. The cable only has two wires, one black and one red. On the board of the raid card to the pin connection says "j_sas_act".
What is this cable for? My guess would be maybe LED status for the front panel or something like that, but I am just guessing....
To the left of the SAS connectors (1) there is the two pin Connector. It is in the sketch below.