The Sun SF12k/SF15k system controller is a Sun Netra CP1500 or CP2040 board.

The image to the left shows the onboard DIN-8 male connector that will fit the DIN-8 female socket. To make a cable for communicating with the system controller, you will require a DIN-8M connector, a length of UTP cable and an appropriate serial connector for your application. I am listing DB25 and DB9 as possible terminations.