Pentax PocketJet 3 - Manual (Page 33)

Parity may be set to odd, even, or none.
Flow control may be set to hardware (sometimes known as
RTS/CTS), software (sometimes known as XON.XOFF), or both.
It will be a rare instance in which both are set together.
When you have completed your selections, click on the “Save
Config” button to transmit your preferences to the printer.
Note: The new serial parameters will take effect immediately. If
you are sending this configuration data to your printer using
the serial port, then further configuration changes cannot be
communicated to the printer using the serial port until you
change the serial port parameters on your PC to match the
parameters that you just sent to the printer.
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