Panasonic KX-NS500 Installation Manual page 77

4.2.5 Installing/Removing the Optional Service Cards
2.
Position the card in the EXP-M card slot, making sure that the extension bolts are aligned with the holes
in the card and that the tabs on both sides of the card fit into place. Then, holding the card firmly in place,
lower the rear end so that the holes of the card are aligned with the extension bolts.
Installation Manual 77