Lexmark CX943
From the home screen, touch Settings > Device > Accessibility.
Adjust the headphone volume.
Note: The volume resets to the default value after the user exits Accessibility mode or when the printer wakes from Sleep or Hibernate mode.
Launch the on‑screen keypad to adjust the volume of the internal speaker of your printer.
Use the fax darkness setting of your printer to fine-tune image and text quality.