The following instructions detail how to set up an Oki 420 Turbo and Oki 421 Turbo for serial printing. Now this setup is the same as an Oki320 but you must remember to set TOF in order to make it print correctly.

1. Turn printer on SEL and POWER light should come on.
2. Press Shift + SEL key – until Menu light should come on.
3. Press Print key - Current hardware settings of printer should be printed.

Check Rear Feed - Control Form Tear-Off setting. - If it does not say 500 ms, you must change this setting.

1. To change this setting, press the line feed (group) key until the first Rear Feed setting is printed.
2. Then press the form feed (item) key until the Form Tear Off option of the Rear Feed is printed.
3. Then press the park (set) key until the Form Tear Off says 500ms.

Next, check the Serial I/F - Protocol setting. - If it does not say X-ON/X-OFF, you must change this setting.

1. To change this setting, press the line feed (group) key until the first Serial I/F Option is printed.
2. Then press the form feed (item) key until the Protocol option of the Serial I/F Option is printed.
3. Then press the park (set) key until the Protocol says X-ON/X-OFF.

Next, check the Serial I/F Option Baud Rate setting. - If it does not say 9600 BPS (or whatever the serial port baud rate is set to for the connecting port), you must change this setting.

1. To change this setting, press the form feed (item) key until the Baud Rate option of the Serial I/F Option is printed.
2. Then, press the park (set) key until the Baud Rate says 9600 (or whatever the serial port baud rate is set to for the connecting port).

Next, check the Serial I/F Option DSR Signal setting. - If it does not say Invalid, you must change this setting.

1. To change this setting, press the form feed (item) key until the DSR Signal option of the Serial I/F Option is printed.
2. Then, press the park (set) key until the DSR Signal says Invalid.

Press the Shift + SEL key to exit and save the setup.  This will cause the SEL and Power light to come back on, and now we can can move to the last step.

Next, we need to setup TOF (Top of Form).

1. Make sure your invoice form is lined up at the perforation and print an invoice.

     *You will use this to determine which direction to set the first printable line.

2. Push the SELECT button to turn off the SEL light.
3. Press and hold TEAR button, it will go to the default TOF – Keep holding TEAR button
4. While holding TEAR button, press and hold SHIFT button and release TEAR button – Keep holding SHIFT button
5. As you hold the SHIFT button, press MICROFEED UP or MICROFEED DOWN button, depending on if you need to move the print up or down. The red line of the plastic shield on the print head will determine where first line will print. Use this line as guide to help set the TOF.
6. Once you are at the correct position, release all buttons and press the SELECT button to bring the printer back On-Line.
7. Then print an invoice to test the alignment.
8. Repeat process until characters print in the right boxes on your invoice.