Samsung ML-2550 Series - Manual (Page 214)

P ROGRAMME I NSTALLING P RINTER O PTIONS F.7
F
4 Remove the two screws and the bracket from the control
board. You can discard the old bracket.
If you are replacing the network interface card with new
one or the serial interface card, remove the two screws and
the old card.
5 Align the connector on the network or serial interface card
with the connector on the control board. Push the card
firmly into the connector until it is completely inserted into
place.