HP 3500 - Manual (Page 239)

3. Locate an empty EIO slot. Loosen and remove the two retaining screws holding the
cover for the EIO slot onto the printer, and then remove the cover. You will not need
these screws and cover again.
4. Firmly insert the HP Jetdirect print server card into the EIO slot. Insert and tighten the
retaining screws that came with the print server card.
5. Connect the network cable.
ENWW Installing an hp Jetdirect print server card in the hp color LaserJet 3700 series printer 227