This is a replacement breakout cable for the Presonus FireBox. The cable's multi-pin DB-9 connector attaches to the rear of the FireBox and provides input and output of S/PDIF and MIDI. It can be used to attach the S/PDIF output of an instrument or device, and it can transmit 24-bit 96 kHz digital audio signals. The MIDI ports can be used for communication with external MIDI equipment, MIDI programming, MIDI machine control, and MIDI time control. This cable is included when you purchase a new FireBox. This product is a replacement cable in the event you misplace the one that is supplied.