How do I disable the beeper or enable it if it has been disabled?

To disable or enable the beeper (the procedure is the same in both cases)...

1. Ensure that the power supply to the printer is turned on.
2. Press and hold down the Power key (the bottom key on the front panel).
3. Press the OK key (the upper right key on the front panel) five times while the Power key is pressed.
4. Release the Power key.
5. Finally turn the printer off and then on again.