Dell Precision 650 - Manual (Page 117)

5. If you are installing a drive that has its own controller card, install the controller card in an expansion slot.
See the documentation that accompanied the drive and controller card to verify that the configuration is correct for your computer.
6. Connect the power and CD/DVD drive cables to the drive.
If you are adding a drive that has an audio cable, connect the audio cable to the audio connector on the system board.
1 power cable
2 CD/DVD drive cable
3 audio cable (some drives