Epson EU-42 Setup Manual page 28

11. Identify the slots for the ROM module.
12. Insert the module all the way into slot A, making sure that the
gold contact side of the module faces up. The X tab on the left
of the slot will jut out when the module is inserted correctly.
c
22
Setting Up the Printer
Caution:
Do not force the ROM module into the slot.
Be sure to insert the module facing the correct way.
ROM module slot A