Dell OptiPlex 745 - Manual (Page 29)

9. If you are installing a PCI Express card, release the lever on the securing tab, and ensure that the securing tab fits into the notch on the front end of
the card.
10. Gently press down on the card-retention latch to secure the card.
11. If you are installing a serial port adapter, connect the adapter cable to the serial port adapter connector (SER2) on the system board (see System Board
Components ).
1 fully seated card
2 not fully seated card
3 bracket within slot
4 bracket caught outside of slot
1 release tab 4 card-edge connector
2 card-retention latch 5 card connector
3 card
NOTICE: Do not route card cables over or behind the cards. Cables routed over the cards can prevent the computer cover from closing properly or
cause damage to the equipment.