FUJITSU DL9300 - Manual (Page 43)

SETTING UP
2-24 User's Manual
3. To secure a parallel interface cable, flip the fastener clips located
on the printer into the notches on the cable connector. To secure
a serial interface cable, tighten the screws in the cable connector.
4. Attach the other end of the interface cable to your computer.
Gently pull on the cable to verify that it is secure.