The following instructions detail how to set up an Oki 320 Turbo and Oki 321 Turbo for serial printing.
Check Rear Feed - Control Form Tear-Off setting. - If it does not say 500 ms, you must change this setting.
Next, check the Serial I/F - Protocol setting. - If it does not say X-ON/X-OFF, you must change this setting.
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.
Next, check the Serial I/F Option DSR Signal setting. - If it does not say Invalid, you must change this setting.
Press the Shift + SEL key to exit and save the setup. This will cause the SEL and Power light to come back on, and the printer setup is complete.