Lexmark MX931
Turn off the printer.
Apply isopropyl alcohol to a damp, soft, lint-free cloth, and then wipe the surface around the USB port.
Install the wireless module.
Notes:
Check for a gap between the module and the printer, then attach the spacer module if necessary.
Attach the NFC card.
Turn on the printer.
Security options against FragAttack
Know how to replace the standard tray with the envelope tray.