Dell Precision T7400 (Late 2007) - Manual (Page 269)

Adding and Replacing Parts 269
8 Gently slide the drive into place until you hear a click or feel the drive
securely installed.
9 Attach the power and data cables to the optical drive.
NOTICE: Do not attach a SATA optical drive to an HDD connector on the system
board or it will not function. Attach SATA optical drives to the connectors labeled
10 If you are installing a SATA drive, connect the other end of the data cable
to a SATA connector on the system board.
1 sliding-plate lever 2 optical drive
1
2