Dell OptiPlex GX260 Series System User's Manual page 91

Your computer supports up to two IDE devices. Connect hard drives to the connector labeled IDE1, and connect CD/DVD
drives to the connector labeled IDE2.
Connecting Drive Cables
When you install a drive, you connect two cables—a DC power cable and an interface cable—to the back of the drive.
Power Cable Connector
1 power cable
2 power input connector
Drive Interface Connector
1 interface connector
2 colored stripe on cable
3 interface cable
Most interface connectors are keyed for correct insertion; that is, a notch or a missing pin on one connector matches a tab or
a filled-in hole on the other connector. Keyed connectors ensure that the pin-1 wire in the cable (indicated by the colored
stripe along one edge of the cable) goes to the pin-1 end of the connector. The pin-1 end of a connector on a board or a card
is usually indicated by a silk-screened "1" printed directly on the board or card.
NOTICE: When you connect an interface cable, do not place the colored stripe away from pin 1 of the connector.
Reversing the cable prevents the drive from operating and could damage the controller, the drive, or both.